I made an awsome video comparing these both actioncams on my mountainbike and on a Tyco Rebound 4×4 RC car and also tested the sound of both cams
SJcam SJ5000 has a more appealing picture out of cam, but terrible sound quality.
The Xiaomi Yi video doesn’t look as nice, colors are flat and contrastless, it looks less sharp than the the SJ5000, but if you work with a video editor, you can add a lot more details in the darker parts, also the sound is better.
SJ5000 WiFi: https://goo.gl/XRDFvA
SJ5000 Plus: https://goo.gl/W4kJlq
SJ5000x WiFi Elite: https://goo.gl/LpCjJG
Nice set with all the mounts you’ll need: https://goo.gl/087FyK