It really just comes down to your personal preference.
If you want something more subtle while sacrificing a bit of video quality, go with the contour. Some people don't like how protruding the gopro is.
Personally I'd go with the better image quality of the go pro, but I don't really care how it looks mounted on my helmet.
So it's up to you!
All that is gold does not glitter, not all those who wander are lost.