I've got the Sony HDR-AS15. Liked the price, and the availability of a standard tripod mount on the waterproof case it came with. As for image quality, the output you get on the SD card doesn't match the capability of the sensor- looking at the raw output from the microHDMI port vs the encoded files- there needs to be many more bitrate options. The top end GoPro models have that right. I don't always need 1080p, and so most of the time I just use 720, but I really want an SHQ 720p mode that cranks the bitrate- that would be beautiful. I've also used it quite a bit for still frame interval timelapse, and have been similarly disappointed in the grainy over-compressed look of them.

verdict: good value, kind of pricey accessories for what you get, just adequate video quality, excellent audio for an action cam, good flexibility (video and timelapse options, HDMI out, mic in, decent waterproof case).