http://www.wired.com/2016/07/review-yi- ... on-camera/
The Yi is almost exactly a GoPro. It looks exactly like a GoPro. Everybody I showed it to thought it was a GoPro. Even the font in its menu system is suspiciously familiar, as is the latch on the waterproof housing. It can shoot at the same high speeds as the Hero4 Black. The pattern of beeps for starting and stopping recording is the same. So what’s the difference? The Hero4 Black costs $500, and the Yi 4K costs $250. But wait, there’s more.
When GoPro made the Hero4 line, it decided that the mid-tier Silver edition would have a touchscreen on the back, but that the top-tier Black edition would not. The Yi 4K basically took the Black edition and put the Silver edition’s screen on it, but it’s larger (2.19 inches versus 1.5 inches), higher resolution (330 pixels per inch), and more responsive than GoPro’s.
Sidd