Saw this deal from slickdeals, looks like a good deal if you don't need the 4k/60fps feature of the new Yi 4k+.
Reviews and comparison
GOPRO HERO5 BLACK VS. YI 4K+ VS. YI 4K
XIAOMI YI 4K+ VS YI 4K
- Records 4K/30fps (100mbps), 1080p/120fps, 720p/240fps video and 12MP photos using a 155° wide-angle lens with F2.8 aperture
- Built-in 2.2" LCD touchscreen with 640 x 360 high resolution for easy previewing and shooting. Designed with Gorilla Glass Retina to resist scratches and daily impact
- World's leading technologies: Ambarella A9SE75 Chip, Sony IMX377 Image Sensor, 7 layers of glass lenses, and Electronic Image Stabilization (EIS) to guarantee ultra-clear and stable 4K video resolution and 12M pixel photos even in low light conditions
- Rechargeable 1400mAh high capacity 4.4V lithium-ion battery records up to 120 minutes of 4K/30fps video with a single charge. High performing cooling system prevents YI 4K Action Camera of overheating and enables stable video recording. Built-in Bluetooth and high speed 5GHz/2.4GHz Wi-Fi support for wireless remote * control and the YI Action App for instant photo and video editing
- Must use compatible microSD, supports most High Speed Class 10, UHS Speed Class 1 (U1) and UHS Speed Class 3(U3), 16GB-128GB with FAT32 format. See recommended list in photo gallery for more info
Hard to justify when there are a million SJCam clones available for less than quarter of the price.