I have been using this phones from 4 months. It has some good and some bad qualities. Here I am just mentioning bad qualities :
1. FM radio is not good : only 4 channels can be stored, low signal quality.
2. Even in Loudspeaker mode, voice is very-very low.
3. If I open 2-3 apps, phone hangs.
The worst thing ( which is seen by me and lots of my friends also) is that call drops in between without any notifications. And phone hangs when you try to call and at the same time some one else is calling you.
The call drop thing is very-very-very annoying.