The Xiaomi Mi Mix comes with Android Marshmallow and MIUI 8.0. MIUI is one of the most extensive customizations of Android to date. It has a big following in China where Google services are not accessible so Xiaomi refocused the ecosystem away from Mountain View's services. For those living elsewhere, the official and not-so-official importers are providing various international (global) ROMs, which come stripped from the Chinese services, in favor of Google's.
MIUI 8 starts off with a recent overhaul on the visuals but the new icons, color scheme, and animations are more of a refinement rather than a departure. But the looks are just a minor part of the way MIUI is different from stock Android.
The highlights of the MIUI8 features are Dual Apps and dual spaces. Dual Apps means you can have two instances of the same app on your device, so you can, for example, have two WhatsApp accounts on the same phone, one for each SIM, something you couldn't do before.
Any app can become a dual-app - you just need to enable it from settings. The second instance has a yellow indication on its app icon, so you'll always know which instance you are opening.
Dual spaces lets you have two different workspaces on your device, each with its own set of apps, customizations, and image gallery, and you can enter a custom passcode or a different fingerprint to enter either of the space.
Configuring a second space is very easy and straightforward. After setting a different PIN and/or fingerprint, you can import and share photos, files, and apps between the two spaces, or choose to keep those entirely separated. You can also opt to view notifications from the other space, so you won't miss anything.
The new Quick Ball option with quick navigation controls takes a major role in the Mix because of its huge screen. There is a dedicated Quick Ball shortcut on the navigation bar at the bottom of the screen. By the way, Xiaomi allows you to use swipe up and down on the nav bar if you want to hide it, too.
Those were the highlights of the MIUI 8. Everything else is the usual Android business. The lockscreen is fairly standard (time, notifications, a couple of shortcuts), but once you set up the fingerprint reader, you'll rarely see it anyway.
The always-on fingerprint sensor proved capable, but it's not as accurate as the one we've used on the Mi 5s Plus. It recognized our registered finger correctly only 6 out of 10 times, which is about average.
MIUI has a simple philosophy - every shortcut, plus widgets of your choosing, are dropped on the homescreen. You get a docked menu for the most commonly used apps, of course. The homescreen also supports wallpaper carousel, you can enjoy different beautiful wallpapers all the time.
The notification drawer has a consolidated list of quick toggles, notifications, and a weather panel at the top that changes color and animation according to the weather.
The app switcher feels like it came out of iOS - apps are either represented by their icons, in a single horizontal row, or by appropriate thumbnails in the same manner.
Finally, themes are fully supported and several are available out of the box. You can download more - they change wallpapers, lockscreen style, system icons and font, sounds too.