diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
index a7702d1..b47c51c 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
@@ -46,7 +46,7 @@
   @property({type: Boolean})
   showTooltipBelow = false;
 
-  private readonly restApiService = appContext.restApiService;
+  private readonly userService = appContext.userService;
 
   override connectedCallback() {
     super.connectedCallback();
@@ -60,7 +60,7 @@
    */
   setMode(newMode: DiffViewMode) {
     if (this.saveOnChange && this.mode && this.mode !== newMode) {
-      this.restApiService.savePreferences({diff_view: newMode});
+      this.userService.updatePreferences({diff_view: newMode});
     }
     this.mode = newMode;
     let announcement;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.ts b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.ts
index aa97394..8b06c75 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_test.ts
@@ -19,7 +19,7 @@
 import './gr-diff-mode-selector';
 import {GrDiffModeSelector} from './gr-diff-mode-selector';
 import {DiffViewMode} from '../../../constants/constants';
-import {stubRestApi} from '../../../test/test-utils';
+import {stubUsers} from '../../../test/test-utils';
 
 const basicFixture = fixtureFromElement('gr-diff-mode-selector');
 
@@ -47,7 +47,7 @@
   });
 
   test('setMode', () => {
-    const saveStub = stubRestApi('savePreferences');
+    const saveStub = stubUsers('updatePreferences');
 
     // Setting the mode initially does not save prefs.
     element.saveOnChange = true;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
index 5b48345..c7a462e 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
@@ -113,6 +113,7 @@
 import {changeComments$} from '../../../services/comments/comments-model';
 import {takeUntil} from 'rxjs/operators';
 import {Subject} from 'rxjs';
+import {preferences$} from '../../../services/user/user-model';
 
 const ERR_REVIEW_STATUS = 'Couldn’t change file review status.';
 const LOADING_BLAME = 'Loading blame...';
@@ -361,11 +362,20 @@
     this._getLoggedIn().then(loggedIn => {
       this._loggedIn = loggedIn;
     });
+    // TODO(brohlfs): This just ensures that the userService is instantiated at
+    // all. We need the service to manage the model, but we are not making any
+    // direct calls. Will need to find a better solution to this problem ...
+    assertIsDefined(appContext.userService);
+
     changeComments$
       .pipe(takeUntil(this.disconnected$))
       .subscribe(changeComments => {
         this._changeComments = changeComments;
       });
+
+    preferences$.pipe(takeUntil(this.disconnected$)).subscribe(preferences => {
+      this._userPrefs = preferences;
+    });
     this.addEventListener('open-fix-preview', e => this._onOpenFixPreview(e));
     this.cursor.replaceDiffs([this.$.diffHost]);
     this._onRenderHandler = (_: Event) => {
@@ -1148,12 +1158,6 @@
 
     promises.push(this._getDiffPreferences());
 
-    promises.push(
-      this._getPreferences().then(prefs => {
-        this._userPrefs = prefs;
-      })
-    );
-
     if (!this._change) promises.push(this._getChangeDetail(this._changeNum));
 
     if (!this._changeComments) this._loadComments(value.patchNum);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
index 2c4750a..0c7abc8 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
@@ -1524,6 +1524,7 @@
       assert.equal(element._getDiffViewMode(), 'SIDE_BY_SIDE');
 
       // User prefs but no change view state set.
+      element.changeViewState.diffMode = undefined;
       element._userPrefs = {default_diff_view: 'UNIFIED_DIFF'};
       assert.equal(element._getDiffViewMode(), 'UNIFIED_DIFF');
 
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
index 3533fd6..256e956 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view.ts
@@ -246,6 +246,7 @@
       this.$.diffPrefs.loadData(),
     ];
 
+    // TODO(dhruvsri): move this to the service
     promises.push(
       this.restApiService.getPreferences().then(prefs => {
         if (!prefs) {
diff --git a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
index 8194d5b..1165f1e 100644
--- a/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
+++ b/polygerrit-ui/app/elements/settings/gr-settings-view/gr-settings-view_test.ts
@@ -273,7 +273,7 @@
     stubRestApi('savePreferences').callsFake(prefs => {
       assertMenusEqual(prefs.my, preferences.my);
       assert.equal(prefs.publish_comments_on_push, true);
-      return Promise.resolve(new Response());
+      return Promise.resolve(createDefaultPreferences());
     });
 
     // Save the change.
@@ -294,7 +294,7 @@
 
     stubRestApi('savePreferences').callsFake(prefs => {
       assert.equal(prefs.publish_comments_on_push, true);
-      return Promise.resolve(new Response());
+      return Promise.resolve(createDefaultPreferences());
     });
 
     // Save the change.
@@ -315,7 +315,7 @@
 
     stubRestApi('savePreferences').callsFake(prefs => {
       assert.equal(prefs.work_in_progress_by_default, true);
-      return Promise.resolve(new Response());
+      return Promise.resolve(createDefaultPreferences());
     });
 
     // Save the change.
@@ -348,7 +348,7 @@
 
     stubRestApi('savePreferences').callsFake(prefs => {
       assertMenusEqual(prefs.my, element._localMenu);
-      return Promise.resolve(new Response());
+      return Promise.resolve(createDefaultPreferences());
     });
 
     await element._handleSaveMenu();
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
index f808e38..8322682 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
@@ -73,6 +73,8 @@
 
   private readonly restApiService = appContext.restApiService;
 
+  private readonly userService = appContext.userService;
+
   disconnected$ = new Subject();
 
   override connectedCallback() {
@@ -106,7 +108,7 @@
     if (scheme && scheme !== this.selectedScheme) {
       this.set('selectedScheme', scheme);
       if (this._loggedIn) {
-        this.restApiService.savePreferences({
+        this.userService.updatePreferences({
           download_scheme: this.selectedScheme,
         });
       }
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.ts b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.ts
index c932a2e..ef712ac 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.ts
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands_test.ts
@@ -23,6 +23,7 @@
 import {createPreferences} from '../../../test/test-data-generators';
 import * as MockInteractions from '@polymer/iron-test-helpers/mock-interactions';
 import {GrShellCommand} from '../gr-shell-command/gr-shell-command';
+import {createDefaultPreferences} from '../../../constants/constants';
 
 const basicFixture = fixtureFromElement('gr-download-commands');
 
@@ -95,7 +96,7 @@
     test('saves scheme to preferences', () => {
       element._loggedIn = true;
       const savePrefsStub = stubRestApi('savePreferences').returns(
-        Promise.resolve(new Response())
+        Promise.resolve(createDefaultPreferences())
       );
 
       flush();
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
index ae2bda0..63576c2 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
@@ -682,19 +682,27 @@
     });
   }
 
-  savePreferences(prefs: PreferencesInput): Promise<Response> {
+  savePreferences(
+    prefs: PreferencesInput
+  ): Promise<PreferencesInfo | undefined> {
     // Note (Issue 5142): normalize the download scheme with lower case before
     // saving.
     if (prefs.download_scheme) {
       prefs.download_scheme = prefs.download_scheme.toLowerCase();
     }
 
-    return this._restApiHelper.send({
-      method: HttpMethod.PUT,
-      url: '/accounts/self/preferences',
-      body: prefs,
-      reportUrlAsIs: true,
-    });
+    return this._restApiHelper
+      .send({
+        method: HttpMethod.PUT,
+        url: '/accounts/self/preferences',
+        body: prefs,
+        reportUrlAsIs: true,
+      })
+      .then((response: Response) =>
+        this.getResponseObject(response).then(
+          obj => obj as unknown as PreferencesInfo
+        )
+      );
   }
 
   saveDiffPreferences(prefs: DiffPreferenceInput): Promise<Response> {
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
index 1aee75a..a60a1ef 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface_test.js
@@ -386,7 +386,8 @@
       });
 
   test('savPreferences normalizes download scheme', () => {
-    const sendStub = sinon.stub(element._restApiHelper, 'send');
+    const sendStub = sinon.stub(element._restApiHelper, 'send').returns(
+        Promise.resolve(new Response()));
     element.savePreferences({download_scheme: 'HTTP'});
     assert.isTrue(sendStub.called);
     assert.equal(sendStub.lastCall.args[0].body.download_scheme, 'http');
diff --git a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
index cd3fab3..1378211 100644
--- a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
+++ b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
@@ -209,7 +209,9 @@
     errFn?: ErrorCallback
   ): Promise<ChangeInfo | null>;
 
-  savePreferences(prefs: PreferencesInput): Promise<Response>;
+  savePreferences(
+    prefs: PreferencesInput
+  ): Promise<PreferencesInfo | undefined>;
 
   getDiffPreferences(): Promise<DiffPreferencesInfo | undefined>;
 
diff --git a/polygerrit-ui/app/services/user/user-service.ts b/polygerrit-ui/app/services/user/user-service.ts
index 0612aca..125d20c 100644
--- a/polygerrit-ui/app/services/user/user-service.ts
+++ b/polygerrit-ui/app/services/user/user-service.ts
@@ -14,7 +14,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import {AccountDetailInfo, PreferencesInfo} from '../../types/common';
+import {
+  AccountDetailInfo,
+  PreferencesInfo,
+  PreferencesInput,
+} from '../../types/common';
 import {from, of} from 'rxjs';
 import {account$, updateAccount, updatePreferences} from './user-model';
 import {switchMap} from 'rxjs/operators';
@@ -39,4 +43,13 @@
         updatePreferences(preferences ?? createDefaultPreferences());
       });
   }
+
+  updatePreferences(prefs: PreferencesInput) {
+    this.restApiService
+      .savePreferences(prefs)
+      .then((newPrefs: PreferencesInfo | undefined) => {
+        if (!newPrefs) return;
+        updatePreferences(newPrefs);
+      });
+  }
 }
diff --git a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
index 4be19fd..3bb0c34 100644
--- a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
+++ b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
@@ -83,6 +83,7 @@
 import {
   createDefaultDiffPrefs,
   createDefaultEditPrefs,
+  createDefaultPreferences,
 } from '../../constants/constants';
 import {ParsedChangeInfo} from '../../types/types';
 
@@ -481,8 +482,8 @@
   saveIncludedGroup(): Promise<GroupInfo | undefined> {
     throw new Error('saveIncludedGroup() not implemented by RestApiMock.');
   },
-  savePreferences(): Promise<Response> {
-    return Promise.resolve(new Response());
+  savePreferences(): Promise<PreferencesInfo> {
+    return Promise.resolve(createDefaultPreferences());
   },
   saveRepoConfig(): Promise<Response> {
     return Promise.resolve(new Response());
diff --git a/polygerrit-ui/app/test/test-utils.ts b/polygerrit-ui/app/test/test-utils.ts
index 1cde372..39c30ad 100644
--- a/polygerrit-ui/app/test/test-utils.ts
+++ b/polygerrit-ui/app/test/test-utils.ts
@@ -24,6 +24,7 @@
 import {AuthService} from '../services/gr-auth/gr-auth';
 import {ReportingService} from '../services/gr-reporting/gr-reporting';
 import {CommentsService} from '../services/comments/comments-service';
+import {UserService} from '../services/user/user-service';
 export {query, queryAll, queryAndAssert} from '../utils/common-util';
 
 export interface MockPromise extends Promise<unknown> {
@@ -111,6 +112,10 @@
   return sinon.stub(appContext.commentsService, method);
 }
 
+export function stubUsers<K extends keyof UserService>(method: K) {
+  return sinon.stub(appContext.userService, method);
+}
+
 export function stubStorage<K extends keyof StorageService>(method: K) {
   return sinon.stub(appContext.storageService, method);
 }