You can now flash stock Android 4.4 on your Xiaomi Mi 3 or Mi 4
MIUI is being developed under the wing of Xiaomi and is the stock ROM for its phones, phablets, and tablets. However, owners of the Mi 3 and Mi 4 smartphones, who do not care much about Xiaomi's interface, will now be able to flash stock Android 4.4 KitKat on their devices. A developer at the MIUI forums has published an AOSP version of the Android ROM, compiled using the official kernel, keeping it as vanilla as can be. The latest published ROM also supports over-the-air updates and the developer says that this is how they will be pushed from now on.
There are a lot of people out there who enjoy vanilla Android and some of those who bought a Mi 3 or Mi 4 for their bang-to-buck ratio, rather than MIUI, will be glad to know what they now have a semi-official option to strip it down.
source: MIUI forums (translated) via GSMArena