After a bunch of fiddling around with 808 keychain cameras, I got a Contour Roam. I rode with it for the first time this morning and am impressed with the low light performance. The video is grainy, nothing much can be done about that, and I don't think you'll be making out license plates in low light conditions, but it's pretty good.
I do want to warn people of a couple of things. First, the software (which you must download from the website) requires you to also install Quicktime (if installing on Windows). I don't allow Quicktime on my system so that was a non-starter. I did install on a VM just to try it out. The software is the only documented way to change the settings on the camera, and for me it only gave me the options of frame rate (30 or 25) and allowed me to set the date/time. I had to search around and found a TXT file that can be edited to set the other settings on the camera, including resolution, beep on/off, volume level, etc.
Also though they talk about sharing through YouTube and other services, it looks to me like you must upload to their site, then they will push to a linked YouTube (or whatever) account. I did not set up an account with them because I have no intention to give them information. I would be very careful when setting up an account, it's possible that they will present you with a EULA that gives them rights to your videos. I don't know that but I wouldn't be surprised.
There is no manual for the software, and it is NOT very intuitive. They have said on the forums that they are "working on a manual" - for over a year now. It should take a decent tech writer about a week to write a manual, but apparently it's not a priority for them.
There have been reports that the window in front of the lens is very susceptible to scratching and it's unclear whether they have a way to get it replaced. They say they're "working" on a (paid) service to replace scratched windows.
I'm a little nervous that the battery isn't user-replaceable - I will be using the thing for 90 minutes a day, about 250 days a year, so it's likely that in a year or two I'll need a replacement. They again say they're "working" on a (paid) service to replace dead batteries. If they "work" as hard at this as they do on putting out a manual, I may have to junk the camera when the battery dies in a year or two.
I was very unimpressed with the mounts - they only secure via sticky tape and they are not curved to mate properly with a helmet though one of them is somewhat flexible. I designed my own and printed one on a 3D printer, you can see it at
http://www.thingiverse.com/thing:22212
In the end, it's a really nice camera with good video quality, but you should expect to provide your own video editing software, and you should expect to either have to make a mount or pay up to $40 for a better mount than what comes with it. Maybe I'm wrong about the mounts but I sure don't trust them.