I have a Contour Roam and a Roam2. It could be just my imagination but I think the Roam2 has slightly better video quality than the original Roam.
I think GoPro and Countour produce some excellent video but I went with Contour over GoPro for many of the reasons the guys have already mentioned: battery life, compactness, and most important, ease of operation. A lot of my video is shot in short segments (less than a minute), turning the camera on and off while on the move. I can operate the camera even while wearing heavy mittens. Obviously the Roam does not have a viewing screen so if that’s important, the Roam is out.
I haven’t explored a lot of alternative helmet mounting options and have only used the standard mounting pads which have somewhat limited mounting angle adjustment. I prefer to not have the helmet in the shot so I made a mounting plate for my modular helmet out of a piece of rubber mallet in order to get it mounted forward enough to clear the helmet and still point directly forward. On my other helmet with the visor, mounting it on the visor worked perfectly. I rotate the lens so the camera is actually mounted sideways on the visor. You can also mount the camera on a standard tripod if need be.
Both good cameras, guess it comes down to which key features are most important.