I am usig mi4i right now and it is an average phone it is sluggish but the camera quality is simply amazing
The selfie shooter is awesome
And back camera can click some amazing pictures with manual mode you can click some amazing shots
The gaming performance is poor there are a lot of frame drops and sometimes it hangs
App loading time is not good
The phone is light in weight but the main factor is that is has only 16gb of memory out of which only 12.5 is usable so its better you buy a new phone at same price like redmi note 3