I have used several Xiaomi products (phone, box, MIUI). I can say their product design and quality are very good. Obviously, they copied hardware design from Apple, but they have proved that they can build high quality products at very low prices, and they are selling phones, tablets, TV boxes, real TVs, earphones, routers. Very few companies in the world can achieve it (Google tried it and didn't go anywhere, remember Nexus Q). It is only matter of time Xiaomi to catch up on their original design capability.
For reference, Smartisan T1 had very good product design. It was done by a English teacher founder with less than $20M funding. All it took was to find a good design firm to help out. While I don't like their copycat, but they are very likely to succeed in the long run.
Big +1 on the Smartisan (锤子). I really like their interface. The Smartisan OS is one of the most thoughtfully and beautifully designed Android systems that I've seen.
For reference, Smartisan T1 had very good product design. It was done by a English teacher founder with less than $20M funding. All it took was to find a good design firm to help out. While I don't like their copycat, but they are very likely to succeed in the long run.