The official announced the good news yesterday. So we will finally get MIUI 6 Rom based on Android 4.4 next Friday.
It is expected to fix some small bugs in the previous leaked version.
http://www.miui.com/thread-1994222-1-1.html
0829 release version bug report:
Sometimes i cannot unlock the screen. There is very long latency(about 10~20s). Someone else also had the same problem. Hope that the dev team can solve this problem very soon.