I have a Contour ROAM, it seems like the GoPros have better low light performance, but I've been mostly happy with my Contour. You can see my videos at
http://www.youtube.com/weshigh to see how they look. The Contours are a little bit less conspicuous on your head. It does add some extra weight which the higher up will have more change on how it feels. The GoPro seems to sit higher, but you can also get a chest mount with GoPro.