Just got mine today, been installing the helmet mounting hardware on my helmet and adjusting the viewing angle. Trouble is, it adjusts in every direction, except up and down, so I had to tape a pencil eraser under the front of the mounting platform it to raise it a bit higher to compensate for the downward angle of the helmet. The way the holes are placed on my helmet, it was the best place to strap the camera on.
It has decent playback, and is sharp and clear enough, sure it's low res, but I didn't want anything that is super high res, I already have a digital camera that can do that, but it isn't suitable to use while bike riding.
I just wanted something that I could use to record video while riding my bike, and not be too much of a memory hog, or attract attention, like Shimagnolo said, it looks like a light.
Going to try it out on the bike tomorrow if I get home early enough when there's still decent light.