There are some bugs in miui and and gets hang even thoigh it has 4gb ram and using it since it has been launched. Although I have the maximum problem of voice from microphone, the microphone doesnt work well and the other person you are on talk with always complaints that he/she not getting the voice clearly.
The finderprint sensor is good but the camera is not so good it is just ok and in this price range it is a good phone and has been trending phone because only mi can afford to make higher ram under lowest cost.
I woult recommend you to buy the phone