The OnePlus One comes with a custom build of CyanogenMod, labeled 11S and it sits on top of Android 4.4.2 KitKat with a confirmed update to Android L when it launches commercially.
Before we start with the in-depth look on the OnePlus One UI, here's a brief one we caught on video.
The CyanogenMod 11S looks more or less the same as CyanogenMod 11 on other rooted, supported devices, but it adds some features, which are exclusive to the OnePlus One. For starters, it has a custom lockscreen that, although nothing special functionality-wise, looks nice. It blurs the wallpaper underneath it and displays notifications on a navy blue-colored canvas below it. A swipe downward will unlock the device, while a swipe to the left will open up the camera.
You can completely disable the custom lockscreen in favor of the standard one. You can also assign button actions to each of the One's buttons. For instance, holding the home button while on the lockscreen, will open up the flashlight app.
The homescreen is a standard affair if you've ever seen stock Android. The only thing that may catch your attention are the rounded icons, which come as default on the One. While they are rather cool on their own, the icons clash with the stock Android icons as they're all square and give the UI an awkward look when you have a myriad of icons in different shapes.
The dock is customizable and features two shortcut icons on either side of the app drawer key. You can move icons around, including the drawer shortcut. There's no Google Now homescreen to the left, though.
You can customize the homescreen the usual way - by adding widgets, folders, homescreens and shortcuts. The widgets are no longer part of the app drawer. You can access the widget list only by a tap and hold on an empty space on the homescreen and selecting the dedicated Widgets shortcut. Most of the widgets are resizable in all directions in order to fit into any tight space.
You can also change the wallpaper, make a screen the default one and even choose from a long list of available transition effects for when you're swiping through homescreens.
The notification area has been improved a bit in CyanogenMod 11S. The notifications appear as they do on any stock Android device - notifications can be expanded and collapsed with a downwards swipe, and the top one is expanded by default (if the app that put up the notification supports it, of course) - but you have the quick toggles on the top and also accessible through their own, neighboring, page. The latter is accessible through the top-right shortcut in the notification area, a two-finger swipe down from the status bar or through a swipe from the edge of the screen.
Your name and photo are displayed in the toggle area as well, but only after you've logged in to Google+ account or after you've manually set them yourself. The quick toggles can be reordered and you can add new one and remove old ones.
The Recent Apps list has remained virtually unchanged. Since this is CyanogenMod you have a kill all shortcut at the top right.
The app drawer of OnePlus One consists of 5 rows of icons on side-scrollable pages.
The settings menu also looks unchanged from stock Android but there are additional options you won't find there. For one CyanogenMod 11S adds a Themes submenu, which allows you to choose different themes, styles, icons, fonts and even boot animations.
You can see a preview of the themes and icon packs included but there's only one boot animation.
The Theme showcase app allows you to hand-pick a number of third-party looks for your UI. Some of them are paid but there are also quality free ones.
As part of the moddable CyanogenMod package you can customize many things about the UI, just as you would on the regular ROM version. The options fall under the Interface submenu and you can customize the status bar, quick settings panel, notification drawer and add gesture shortcuts. The customizations run deep - for instance you can choose whether the battery status icon is a circle, an icon, plain text or even hide it.
You can also choose whether to use the capacitive touch keys below the screen for menu, home and back or enable traditional virtual on-screen buttons for back, home and recent apps. The latter option conveniently disables the capacitive touch keys and their relatively dim backlight.
Quiet hours is another integral part of the CyanogenMod package. It's essentially a Do Not Disturb mode and can be set to work in a specified period of hours and be set to mute various aspects of the notifications. You can mute calls from anyone or allow specific people or groups to get through, mute notifications and system sounds and works like a charm.
Another part of the CyanogenMod package is the Secure Messaging and Privacy Guard. The former allows for encrypted messaging between CM 11 devices, while the latter will let you choose which information on your device an app can access.
Since this is CyanogenMod, many would be wondering if its stable enough for a daily driver. We can attest that it almost never had hiccups and after a software update hasn't shown any hiccups whatsoever. If pure Android is your cup of tea, the OnePlus One is a great option to have. Coupled with the powerful CyanogenMod it's even more functional than Google's own version and adds great and well-needed features.