The Xiaomi Mi 4i is superb phone at this price.
Built quality is awesome.
Display is very crisp and vivid because of Corning OGS display.
The display is not having any protector but I am still using from 4 months without any protector and not had any single scratch.
The sound output is little bit low but its audible.
Earlier phone is heated while using but after recent updates heating is decreased.
The phone does not support memory card, only 12Gb is usable out of 16Gb.
MIUI7 is customised.
Rear camera is great but front is above average.