Since Android is Open Source and almost all the mobile manufacturers are using that for their handsets. Almost 80% of the smartphones are running on Android. However each manufacturers customize their mobile with their own custom UI based Android OS such as MIUI for Xiamoi Mobiles, EMUI for Huawei handsets etc.
Each company will customize the default OS with their own custom functionalities. Usually they will change the overall look and feel of the User Interfaces such as Settings, status bar, lock screen etc. Usually each company will add their own customized version of stock application also in their Custom OS.
Some people loves Custom UI based Android on their mobile rather than the stock Android OS. But for some Android lovers, they prefer stock Android OS for their mobile. Google also promoting Stock Android on handsets which is promoted under Android One Program. As a part of this, many mobile manufactures has partnered with google to make Stock Android based handset. Xiaomi Mi A2 and Mi A2 Lite are the 2 new additions to this.
Lets look into some of the benefits of the Stock Android over Custom UI
Stock Android comes with minimal applications and features. The OS will not comes with preloaded bloatware. Only essential applications are loaded on the handsets. Whereas in the Custom UI, it contains so many pre-installed application which will reduce the storage capacity of the handset.
Since the handset is loaded only with minimum number of applications, the overall speed and performance of the handset will be more better than Custom UI mobiles. You can monitor the same by yourself if you want to compare it with other non-android one device by using any android event logging software.
Increased Battery Life:
The battery life of the Stock Android handset will be always better than the Custom UI handsets. This is because of the minimum number of applications and the minimum customization of the UI.
This is one of the main highlight of the Android One handsets, now, google promises a minimum of 3 years guaranteed update and support for the mobiles. During that time, all the major Android Version update and Security Updates will be delivered to the handsets. And will be released to the handset soon after releasing to the Pixel Devices.
Monthly Security Updates:
Along with the Android update google also provides monthly security updates to each and every Android One Handsets directly. It will make the device more secure.