Redmi note 3 has poor speaker and the part drawback is it is placed at the back, and the sound is not so loud. Again if it is on a surface while playing music, the sound easily gets muffled.
The user interface is not easy, as it runs on acustom ui called miui.
Design wise it is kind of boring, that same metal unibody design and style , it would be better if they put a 2.5D curved glass on the front.
The range of feature is as limited as one can find in any mid range smartphone. Camera is really pathetic at lowlight , other features like ir bluster and fingerprint are not accurate.
Reliability is negative as it have few service centre. Durability wise it is not so hard, if you drop this from even 2 feet, its glass will break easily.
Ofcouse it is not value for money mobile phone around 12 thousand rupees as it has not match minimal requirement of being a good smadtphone.