I've had both Contour and GoPro.
Yes the GoPro (especially now the Hero3/black edition has just come out) has slightly better quality than the countour but the mounting options of the GoPro are just simply too awkward/clumsy/stupid looking compared to the Contour.
The new Contour+2 wins it for me for it's neat package, slimline design, and it's GPS locator.
Any of the cams that don't entertain a removable battery I would not consider. 2.5-3 hours and most of them are flat by then, then it becomes useless.