I got the £100 as a gift for Christmas, really good when I'm on the bike. Not used it on the car yet. Only issue is that you can't see where the camera is pointing, so I might invest in a screen.
Weirdly I bought my brother a cheap one Sj4000 or something, was around £30 and you get all the mounts, plus it has a screen on the back.
Both seem pretty identical video quality wise, though couldn't vouch for reliability and after sale support from the Chinese special..