You can win a Xiaomi Mijia Action Camera! I compared the similar priced YI Lite and Xiaomi Mijia incl. EIS Comparison, Audio Test and Specs.
MGCOOL Explorer 3 was just released offering Image Stabilisation in 4K resolution, a 2" Touchscreen and .h264+ video codec.
YI Lite Action Camera has similar specs compared to original YI camera (Xiaomi YI, YI 2K), but within YI 4K body incl. LCD touch screen and image stabilisation!
At first Sony RX0 looks like the mother of all action cameras. But at closer look: is it? It seems that it can't shoot internal 4K, but up to 1000 fps.