I am using mi 3s prime from last 2 months and its flawless smart features.
1) Great battery life stay for a day and a half easily
2)finger print sensor very easy and accurate .love to use it
3) Ram and storage very fast and lots of space.
4) camera - it has a decent camera with HDR on and also front camera is awesone.
5) Software - it comes with miui 6 which can be updated and it support miui 8 after update which is very user friendly and smooth to operate .
6) All other sensors are working fine.