There are many very minor features that have been added to the latest build of Android M. There is also one very big feature that really excites me! The new System UI Tuner allows you to finally show battery percentage in the status bar! For all these years this has required some sort of hack or mod if you were running stock android, and most certainly required you to be rooted unless you were using some sort of widget. This is now built right into AOSP! The other big part of the System UI Tuner is the ability to enable or disable status bar icons. That means you can finally get rid of that ugly and useless bluetooth icon! You can really clean up your status bar by removing the wifi icon, and even your mobile data icon. This has to be one of the coolest features to be included in AOSP in my opinion!