As the brand itself is renouned for its exeptional quality of products, the Xiaomi Mi4 is a tough competitor for the big giants like Samsung, Sony.etc.
Before buying this phone I was considering the Xiaomi phones as a low cost, cheap quality chinese phones. But to my surprise this Mi4 just made me speechless with its performance and built quality. Now I have been using this phone for more than 3 months without any issues.
In my personal opinion some of the drawbacks are as follows:
a) The lack of an external storage does bothered me. When I dont have much time and have to transfer a huge amount of data from my friends phone to my phone, where SD card exchange was possible( but not with my phone which lacks SD slot) .
b) It comes with 4G band reception which is not for Indian Network service providers.