I've been trying to size these up as well.
An added advantage of the Contour is it claims to be waterproof and every time you see Steve Fisher with it mounted to his helmet he doesn't have it in a waterproof case. Their site says up to 1 meter, which isn't much, but then again if your helmet goes deeper than 3 ft., in most situations, the camera is the least of your worries. So can anyone speak to the contours ability to be submerged without a case? To me that's a huge advantage. The gopro's case is what always fogs, etc. Plus, not having to drop the extra $60 on the case makes the contour much more competitive.
Far as mounting, what is wring with the contour's side helmet mount? Can a tether be used with it?