diff --git a/osc/_private/api_source.py b/osc/_private/api_source.py
index 3af47b63..0be6fbde 100644
--- a/osc/_private/api_source.py
+++ b/osc/_private/api_source.py
@@ -1,7 +1,7 @@
 from . import api
 from .common import format_msg_project_package_options
-from .common import print_msg
 from .. import oscerr
+from ..output import print_msg
 
 
 def add_channels(apiurl, project, package=None, enable_all=False, skip_disabled=False, print_to="debug"):
diff --git a/osc/_private/common.py b/osc/_private/common.py
index 1f3623aa..a27efb34 100644
--- a/osc/_private/common.py
+++ b/osc/_private/common.py
@@ -1,27 +1,4 @@
-import sys
-
-
-def print_msg(*args, print_to="debug"):
-    from .. import conf
-
-    if print_to is None:
-        return
-    elif print_to == "debug":
-        # print a debug message to stderr if config["debug"] is set
-        if conf.config["debug"]:
-            print("DEBUG:", *args, file=sys.stderr)
-    elif print_to == "verbose":
-        # print a verbose message to stdout if config["verbose"] or config["debug"] is set
-        if conf.config["verbose"] or conf.config["debug"]:
-            print(*args)
-    elif print_to == "stdout":
-        # print the message to stdout
-        print(*args)
-    elif print_to == "stderr":
-        # print the message to stderr
-        print(*args, file=sys.stderr)
-    else:
-        raise ValueError(f"Invalid value of the 'print_to' option: {print_to}")
+from ..output.output import print_msg
 
 
 def format_msg_project_package_options(
diff --git a/osc/babysitter.py b/osc/babysitter.py
index 54668f08..78f42c16 100644
--- a/osc/babysitter.py
+++ b/osc/babysitter.py
@@ -21,6 +21,7 @@ from . import commandline
 from . import conf as osc_conf
 from . import core as osc_core
 from . import oscerr
+from . import output
 from .OscConfigParser import configparser
 from .oscssl import CertVerificationError
 from .util.cpio import CpioError
@@ -108,8 +109,8 @@ def run(prg, argv=None):
         except AttributeError:
             body = ''
 
-        _private.print_msg(e.hdrs, print_to="debug")
-        _private.print_msg(body, print_to="debug")
+        output.print_msg(e.hdrs, print_to="debug")
+        output.print_msg(body, print_to="debug")
 
         if e.code in [400, 403, 404, 500]:
             if b'<summary>' in body:
@@ -153,7 +154,7 @@ def run(prg, argv=None):
         print(e.message, file=sys.stderr)
     except oscerr.OscIOError as e:
         print(e.msg, file=sys.stderr)
-        _private.print_msg(e.e, print_to="debug")
+        output.print_msg(e.e, print_to="debug")
     except (oscerr.WrongOptions, oscerr.WrongArgs) as e:
         print(e, file=sys.stderr)
         return 2
diff --git a/osc/commandline.py b/osc/commandline.py
index 40669a03..b28c1213 100644
--- a/osc/commandline.py
+++ b/osc/commandline.py
@@ -33,6 +33,7 @@ from . import commands as osc_commands
 from . import conf
 from . import git_scm
 from . import oscerr
+from . import output
 from . import store as osc_store
 from .core import *
 from .grabber import OscFileGrabber
@@ -269,7 +270,7 @@ class MainCommand(Command):
 
     def load_commands(self):
         if IN_VENV:
-            _private.print_msg("Running in virtual environment, skipping loading plugins installed outside the virtual environment.", print_to="stderr")
+            output.print_msg("Running in virtual environment, skipping loading plugins installed outside the virtual environment.", print_to="stderr")
 
         for module_prefix, module_path in self.MODULES:
             module_path = os.path.expanduser(module_path)
@@ -4315,7 +4316,7 @@ Please submit there instead, or use --nodevelproject to force direct submission.
                 except:
                     print('Error while checkout package:\n', package, file=sys.stderr)
 
-            _private.print_msg('Note: You can use "osc delete" or "osc submitpac" when done.\n', print_to="verbose")
+            output.print_msg('Note: You can use "osc delete" or "osc submitpac" when done.\n', print_to="verbose")
 
     @cmdln.alias('branchco')
     @cmdln.alias('bco')
@@ -4466,7 +4467,7 @@ Please submit there instead, or use --nodevelproject to force direct submission.
         if opts.checkout:
             checkout_package(apiurl, targetprj, package, server_service_files=False,
                              expand_link=True, prj_dir=Path(targetprj))
-            _private.print_msg('Note: You can use "osc delete" or "osc submitpac" when done.\n', print_to="verbose")
+            output.print_msg('Note: You can use "osc delete" or "osc submitpac" when done.\n', print_to="verbose")
         else:
             apiopt = ''
             if conf.get_configParser().get("general", "apiurl", fallback=None) != apiurl:
@@ -8888,7 +8889,7 @@ Please submit there instead, or use --nodevelproject to force direct submission.
     @cmdln.option('-S', '--set-bugowner-request', metavar='user',
                   help='Set the bugowner to specified person via a request (or group via group: prefix)')
     @cmdln.option('-U', '--user', metavar='USER',
-                        help='All official maintained instances for the specified USER')
+                        help='All official maintained instances for the specified USER (specified by the username or email)')
     @cmdln.option('-G', '--group', metavar='GROUP',
                         help='All official maintained instances for the specified GROUP')
     @cmdln.option('-d', '--delete', metavar='user',
@@ -9012,6 +9013,12 @@ Please submit there instead, or use --nodevelproject to force direct submission.
                             if repl.lower() != 'y':
                                 searchresult = None
             elif opts.user:
+                if "@" in opts.user:
+                    # resolve email address to login
+                    from . import obs_api
+                    users = obs_api.Person.search(apiurl, email=opts.user)
+                    if users:
+                        opts.user = users[0].login
                 searchresult = owner(apiurl, opts.user, "user", usefilter=filterroles, devel=None)
             elif opts.group:
                 searchresult = owner(apiurl, opts.group, "group", usefilter=filterroles, devel=None)
@@ -9175,16 +9182,26 @@ Please submit there instead, or use --nodevelproject to force direct submission.
         """
         Show fullname and email of a buildservice user
         """
+        from . import obs_api
+        from .output import print_msg
+
         apiurl = self.get_api_url()
         usernames = opts.user
 
         if not usernames:
             usernames = [conf.config["api_host_options"][apiurl]["user"]]
 
-        for name in usernames:
-            user = get_user_data(apiurl, name, 'login', 'realname', 'email')
-            if len(user) == 3:
-                print(f"{user[0]}: \"{user[1]}\" <{user[2]}>")
+        # remove duplicates
+        usernames = list(set(usernames))
+
+        users = obs_api.Person.search(apiurl, login=usernames)
+        users_by_login = {i.login: i for i in users}
+        for username in usernames:
+            user = users_by_login.get(username, None)
+            if not user:
+                print_msg(f"User '{username}' does not exist", print_to="warning")
+                continue
+            print(f'{user.login}: "{user.realname}" <{user.email}>')
 
     @cmdln.name("create-pbuild-config")
     @cmdln.alias('cpc')
@@ -10119,7 +10136,7 @@ Please submit there instead, or use --nodevelproject to force direct submission.
 
     def _load_plugins(self):
         if IN_VENV:
-            _private.print_msg("Running in virtual environment, skipping loading legacy plugins.", print_to="stderr")
+            output.print_msg("Running in virtual environment, skipping loading legacy plugins.", print_to="stderr")
             return
 
         plugin_dirs = [
diff --git a/osc/connection.py b/osc/connection.py
index a5223a7c..856804eb 100644
--- a/osc/connection.py
+++ b/osc/connection.py
@@ -21,10 +21,10 @@ import urllib3.response
 import urllib3.util
 
 from . import __version__
-from . import _private
 from . import conf
 from . import oscerr
 from . import oscssl
+from . import output
 from .util.helper import decode_it
 
 
@@ -690,7 +690,7 @@ class SignatureAuthHandler(AuthHandlerBase):
             return False
 
         if not self.ssh_keygen_path:
-            _private.print_msg("Skipping signature auth because ssh-keygen is not available", print_to="debug")
+            output.print_msg("Skipping signature auth because ssh-keygen is not available", print_to="debug")
             return False
 
         if not self.sshkey_known():
diff --git a/osc/core.py b/osc/core.py
index 682b0096..0965089d 100644
--- a/osc/core.py
+++ b/osc/core.py
@@ -50,6 +50,7 @@ from . import _private
 from . import conf
 from . import meter
 from . import oscerr
+from . import output
 from . import store as osc_store
 from .connection import http_request, http_GET, http_POST, http_PUT, http_DELETE
 from .store import Store
@@ -524,7 +525,7 @@ class Serviceinfo:
                     raise oscerr.PackageNotInstalled(f"obs-service-{cmd[0]}")
                 cmd[0] = "/usr/lib/obs/service/" + cmd[0]
                 cmd = cmd + ["--outdir", temp_dir]
-                _private.print_msg("Run source service:", " ".join(cmd), print_to="verbose")
+                output.print_msg("Run source service:", " ".join(cmd), print_to="verbose")
                 r = run_external(*cmd)
 
                 if r != 0:
@@ -3893,7 +3894,7 @@ def set_devel_project(apiurl, prj, pac, devprj=None, devpac=None, print_to="debu
         devprj,
         devpac,
     )
-    _private.print_msg(msg, print_to=print_to)
+    output.print_msg(msg, print_to=print_to)
 
     package_obj = obs_api.Package.from_api(apiurl, prj, pac)
 
@@ -4811,7 +4812,7 @@ def get_review_list(
             xpath_base = xpath_join(xpath_base, 'action/source/@%(kind)s=\'%(val)s\'', op='or', inner=True)
         xpath = xpath_join(xpath, xpath_base % {'kind': kind, 'val': val}, op='and', nexpr_parentheses=True)
 
-    _private.print_msg(f"[ {xpath} ]", print_to="debug")
+    output.print_msg(f"[ {xpath} ]", print_to="debug")
     res = search(apiurl, request=xpath)
     collection = res['request']
     requests = []
@@ -4952,7 +4953,7 @@ def get_exact_request_list(
     if req_type:
         xpath += f" and action/@type='{req_type}'"
 
-    _private.print_msg(f"[ {xpath} ]", print_to="debug")
+    output.print_msg(f"[ {xpath} ]", print_to="debug")
 
     res = search(apiurl, request=xpath)
     collection = res['request']
@@ -5625,7 +5626,7 @@ def checkout_package(
     oldproj = None
     if conf.config['checkout_rooted']:
         if prj_dir.stem == '/':
-            _private.print_msg(f"checkout_rooted ignored for {prj_dir}", print_to="verbose")
+            output.print_msg(f"checkout_rooted ignored for {prj_dir}", print_to="verbose")
             # ?? should we complain if not is_project_dir(prj_dir) ??
         else:
             # if we are inside a project or package dir, ascend to parent
@@ -5652,7 +5653,7 @@ def checkout_package(
                 root_dots = root_dots / ("../" * n)
 
     if str(root_dots) != '.':
-        _private.print_msg(f"{prj_dir} is project dir of {oldproj}. Root found at {os.path.abspath(root_dots)}", print_to="verbose")
+        output.print_msg(f"{prj_dir} is project dir of {oldproj}. Root found at {os.path.abspath(root_dots)}", print_to="verbose")
         prj_dir = root_dots / prj_dir
 
     if not pathname:
diff --git a/osc/obs_api/__init__.py b/osc/obs_api/__init__.py
index 7bc9a365..37c7a52b 100644
--- a/osc/obs_api/__init__.py
+++ b/osc/obs_api/__init__.py
@@ -1,4 +1,5 @@
 from .package import Package
 from .package_sources import PackageSources
+from .person import Person
 from .project import Project
 from .request import Request
diff --git a/osc/obs_api/enums.py b/osc/obs_api/enums.py
index f7c55be7..3fc8de30 100644
--- a/osc/obs_api/enums.py
+++ b/osc/obs_api/enums.py
@@ -7,6 +7,11 @@ class BlockModes(str, Enum):
     NEVER = "never"
 
 
+class BoolString(str, Enum):
+    TRUE = "true"
+    FALSE = "false"
+
+
 class BuildArch(str, Enum):
     NOARCH = "noarch"
     AARCH64 = "aarch64"
diff --git a/osc/obs_api/person.py b/osc/obs_api/person.py
new file mode 100644
index 00000000..54925d20
--- /dev/null
+++ b/osc/obs_api/person.py
@@ -0,0 +1,71 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+from .enums import BoolString
+from .person_owner import PersonOwner
+from .person_watchlist import PersonWatchlist
+
+
+class Person(XmlModel):
+    XML_TAG = "person"
+
+    login: str = Field(
+    )
+
+    email: Optional[str] = Field(
+    )
+
+    realname: Optional[str] = Field(
+    )
+
+    owner: Optional[PersonOwner] = Field(
+    )
+
+    state: Optional[str] = Field(
+    )
+
+    globalrole_list: Optional[List[str]] = Field(
+        xml_name="globalrole",
+    )
+
+    watchlist: Optional[PersonWatchlist] = Field(
+    )
+
+    ignore_auth_services: Optional[BoolString] = Field(
+    )
+
+    @classmethod
+    def from_api(cls, apiurl: str, username: str):
+        url_path = ["person", username]
+        url_query = {}
+        response = cls.xml_request("GET", apiurl, url_path, url_query)
+        return cls.from_file(response, apiurl=apiurl)
+
+    @classmethod
+    def search(
+        cls,
+        apiurl: str,
+        login: Optional[str] = None,
+        email: Optional[str] = None,
+        realname: Optional[str] = None,
+        state: Optional[str] = None,
+        **kwargs,
+    ) -> List["Person"]:
+        from xml.etree import ElementTree as ET
+        from ..util.xpath import XPathQuery as Q
+
+        url_path = ["search", "person"]
+        url_query = {
+            "match": Q(
+                login=login,
+                email=email,
+                realname=realname,
+                state=state,
+                **kwargs,
+            ),
+        }
+        response = cls.xml_request("GET", apiurl, url_path, url_query)
+        root = ET.parse(response).getroot()
+        assert root.tag == "collection"
+        result = []
+        for node in root:
+            result.append(cls.from_xml(node, apiurl=apiurl))
+        return result
diff --git a/osc/obs_api/person_owner.py b/osc/obs_api/person_owner.py
new file mode 100644
index 00000000..d799baa1
--- /dev/null
+++ b/osc/obs_api/person_owner.py
@@ -0,0 +1,9 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+
+
+class PersonOwner(XmlModel):
+    XML_TAG = "owner"
+
+    userid: str = Field(
+        xml_attribute=True,
+    )
diff --git a/osc/obs_api/person_watchlist.py b/osc/obs_api/person_watchlist.py
new file mode 100644
index 00000000..defdf39f
--- /dev/null
+++ b/osc/obs_api/person_watchlist.py
@@ -0,0 +1,20 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+from .person_watchlist_package import PersonWatchlistPackage
+from .person_watchlist_project import PersonWatchlistProject
+from .person_watchlist_request import PersonWatchlistRequest
+
+
+class PersonWatchlist(XmlModel):
+    XML_TAG = "watchlist"
+
+    project_list: Optional[List[PersonWatchlistProject]] = Field(
+        xml_name="project",
+    )
+
+    package_list: Optional[List[PersonWatchlistPackage]] = Field(
+        xml_name="package",
+    )
+
+    request_list: Optional[List[PersonWatchlistRequest]] = Field(
+        xml_name="request",
+    )
diff --git a/osc/obs_api/person_watchlist_package.py b/osc/obs_api/person_watchlist_package.py
new file mode 100644
index 00000000..cb591b18
--- /dev/null
+++ b/osc/obs_api/person_watchlist_package.py
@@ -0,0 +1,13 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+
+
+class PersonWatchlistPackage(XmlModel):
+    XML_TAG = "package"
+
+    name: str = Field(
+        xml_attribute=True,
+    )
+
+    project: str = Field(
+        xml_attribute=True,
+    )
diff --git a/osc/obs_api/person_watchlist_project.py b/osc/obs_api/person_watchlist_project.py
new file mode 100644
index 00000000..3943eede
--- /dev/null
+++ b/osc/obs_api/person_watchlist_project.py
@@ -0,0 +1,9 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+
+
+class PersonWatchlistProject(XmlModel):
+    XML_TAG = "project"
+
+    name: str = Field(
+        xml_attribute=True,
+    )
diff --git a/osc/obs_api/person_watchlist_request.py b/osc/obs_api/person_watchlist_request.py
new file mode 100644
index 00000000..2b14132e
--- /dev/null
+++ b/osc/obs_api/person_watchlist_request.py
@@ -0,0 +1,9 @@
+from ..util.models import *  # pylint: disable=wildcard-import,unused-wildcard-import
+
+
+class PersonWatchlistRequest(XmlModel):
+    XML_TAG = "request"
+
+    number: str = Field(
+        xml_attribute=True,
+    )
diff --git a/osc/output/__init__.py b/osc/output/__init__.py
index 65665c7d..410727df 100644
--- a/osc/output/__init__.py
+++ b/osc/output/__init__.py
@@ -1,5 +1,6 @@
 from .key_value_table import KeyValueTable
 from .input import get_user_input
+from .output import print_msg
 from .tty import colorize
 from .widechar import wc_ljust
 from .widechar import wc_width
diff --git a/osc/output/output.py b/osc/output/output.py
new file mode 100644
index 00000000..879d238f
--- /dev/null
+++ b/osc/output/output.py
@@ -0,0 +1,41 @@
+import sys
+from typing import Optional
+
+from . import tty
+
+
+def print_msg(*args, print_to: Optional[str] = "debug"):
+    """
+    Print ``*args`` to the ``print_to`` target:
+      - None: print nothing
+      - debug: print() to stderr with "DEBUG:" prefix if config["debug"] is set
+      - verbose: print() to stdout if config["verbose"] or config["debug"] is set
+      - error: print() to stderr with red "ERROR:" prefix
+      - warning: print() to stderr with yellow "WARNING:" prefix
+      - stdout: print() to stdout
+      - stderr: print() to stderr
+    """
+    from .. import conf
+
+    if print_to is None:
+        return
+    elif print_to == "debug":
+        # print a debug message to stderr if config["debug"] is set
+        if conf.config["debug"]:
+            print("DEBUG:", *args, file=sys.stderr)
+    elif print_to == "verbose":
+        # print a verbose message to stdout if config["verbose"] or config["debug"] is set
+        if conf.config["verbose"] or conf.config["debug"]:
+            print(*args)
+    elif print_to == "error":
+        print(tty.colorize("ERROR:", "red,bold"), *args, file=sys.stderr)
+    elif print_to == "warning":
+        print(tty.colorize("WARNING:", "yellow,bold"), *args, file=sys.stderr)
+    elif print_to == "stdout":
+        # print the message to stdout
+        print(*args)
+    elif print_to == "stderr":
+        # print the message to stderr
+        print(*args, file=sys.stderr)
+    else:
+        raise ValueError(f"Invalid value of the 'print_to' option: {print_to}")
diff --git a/osc/util/models.py b/osc/util/models.py
index ebcb8b40..28b21ef1 100644
--- a/osc/util/models.py
+++ b/osc/util/models.py
@@ -443,7 +443,7 @@ class BaseModel(metaclass=ModelMeta):
             value = getattr(self, name)
             if value is not None and field.is_model:
                 result[name] = value.dict()
-            if value is not None and field.is_model_list:
+            elif value is not None and field.is_model_list:
                 result[name] = [i.dict() for i in value]
             else:
                 result[name] = value
diff --git a/tests/test_output.py b/tests/test_output.py
index 1b7337ec..49166837 100644
--- a/tests/test_output.py
+++ b/tests/test_output.py
@@ -3,8 +3,9 @@ import io
 import unittest
 
 import osc.conf
-from osc._private import print_msg
 from osc.output import KeyValueTable
+from osc.output import print_msg
+from osc.output import tty
 
 
 class TestKeyValueTable(unittest.TestCase):
@@ -118,6 +119,22 @@ class TestPrintMsg(unittest.TestCase):
         self.assertEqual("foo bar\n", stdout.getvalue())
         self.assertEqual("", stderr.getvalue())
 
+    def test_error(self):
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+        with contextlib.redirect_stdout(stdout), contextlib.redirect_stderr(stderr):
+            print_msg("foo", "bar", print_to="error")
+        self.assertEqual("", stdout.getvalue())
+        self.assertEqual(f"{tty.colorize('ERROR:', 'red,bold')} foo bar\n", stderr.getvalue())
+
+    def test_warning(self):
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+        with contextlib.redirect_stdout(stdout), contextlib.redirect_stderr(stderr):
+            print_msg("foo", "bar", print_to="warning")
+        self.assertEqual("", stdout.getvalue())
+        self.assertEqual(f"{tty.colorize('WARNING:', 'yellow,bold')} foo bar\n", stderr.getvalue())
+
     def test_none(self):
         stdout = io.StringIO()
         stderr = io.StringIO()
@@ -134,6 +151,14 @@ class TestPrintMsg(unittest.TestCase):
         self.assertEqual("foo bar\n", stdout.getvalue())
         self.assertEqual("", stderr.getvalue())
 
+    def test_stderr(self):
+        stdout = io.StringIO()
+        stderr = io.StringIO()
+        with contextlib.redirect_stdout(stdout), contextlib.redirect_stderr(stderr):
+            print_msg("foo", "bar", print_to="stderr")
+        self.assertEqual("", stdout.getvalue())
+        self.assertEqual("foo bar\n", stderr.getvalue())
+
 
 if __name__ == "__main__":
     unittest.main()