Xiaomi has a great popularity because of their great phones launching at an affordable price. The redmi note 4 is good handset according to the price perspective which is Rs. 12999/- for 4 GB RAM and 64GB ROM variant. The audio output is not that loud as Marshall London or HTC 10 but its better than Redmi note 3 and its much more clear on Redmi note 4. In terms of build quality its sort of premium phone thanks to the full metallic body and chrome finishing on the edges.
I have used both Redmi Note 3 and Note 4 and did find that in some cases the redmi note 4 does some excellent job as compared to redmi note 4. You get improved camera. I was a bit confused as Xiaomi has reduced the pixel in redmi note 4 but then I understood that you get 1.12 micro that is way better than of redmi note 3. I was not sure regarding that explanation so I decided to compare and really the camera was better. Also you get big battery life that is 4100 mAh that last about one and a half days of normal usage and about 1 day of heavy usage but again that was my experience and it may vary from person to person. The Snapdragon 625 chipset which is very much power efficient so you get better battery life. The phone has almost all type of sensors which is really great.
But there are some cons also like it does not support fast charging and the chipset is not that fast as others like Snapdragon 652, 820 and 821 and thats it. According to me the phone gives a good value for money.
So should you upgrade for redmi note 3 to redmi note 4 ?
So according to me if you have redmi note 3 then you may not necessarily upgrade to redmi note 4 but you dont have a Xiaomi phone then you may choose redmi note 4.