One plus 3 is a nice phone. It is a phone with features like phone which costs us around 35000 and above phones. People are able to get flasgship experience in just 28k.
As no phone is perfect, so it also have cons and pros both. But its pros are more than its cons.
Pros :
Excellent day light camera
Light oxygen os
Excellent alluminium body feels good in hand
Best in class processor snapgragon 820
Sufficient internal storage 64gb
Stock android experience
Alert slider helps a lot to silent the phone physically
Optic amoled display
Black color is nicely dispalyed
And many more
Cons :
Low light camera is ok
Little heating while playing heavy games
Some glitches
Back bit slippery
No sd card support
Overall if you want a flagship experience at low price it would be a great deal or one plus 3t is also a good choice. But there is only a little difference betweeen both of them.