Just tired out Ivan’s Android 5.0.2 Lollipop rom for the Mi 3. It’s actually good enough for daily use because he fixed the deep sleep issue which caused the phone to suddenly reboot.
The only bug left seems to be that the NFC still does not work. Had some problems with the Play Store that it could not download several apps at the same time, but the bug went away when I tried to look at the problem (wtf).
You need to install ClockworkMod Recovery to be able to install the rom.