Only problem in mi4i is it doesnot support memory card and has only 16GB internal memory. I will explain every features of phone one by one:
1st I want yo tell that you will get every app which is required to run phone efficient inbuilt ex cleaner , any virus scanner , data counter e.t.c
Camera is best
It has some performance lag.
Look is vey good
Slim phone and very light
Different color option available .
Beat phone in this price.
You will be fan of miui interface after using as it bundles all usefull application.