I recently bought the Mi LED Smart TV 4 ( 55) and I must say it's quite impressive. The picture quality is really good, colors are vibrant and clarity is top notch. But I felt sound could have been better, sometimes its not that clear and lacks bass.
The interface is smooth and user friendly, although sometimes it gets little slow. The remote is pretty simple and easy to use but voice command feature don't always work as expected.
One thing I didn't like is the placement of ports, it's kinda hard to reach specially if TV is wall mounted. Also, the stand is bit wobbly, doesn't feel that sturdy.
Overall, for the price, it's a great deal but there are few areas where it could improve.