I've only ever owned a HD Hero and I can say I love it. I'm pretty sure Contours don't have 60 fps and you have to plug them into a computer to change the settings so thats what killed them for me. If you don't mind that, stuff then go with the Contour.
I have a contour and love it. It does have a 60fps setting but you do need to hookup to a computer to really play around with the settings. I think the contour is better because they are all water resistant (without having a case on) so they are smaller and have a much lower profile. Contour use to suck for mounts (they were limited) compared to gopro but they are adding more and more and seem to have a good selection now. They both have similar video qualities expect I've found contour is a bit more "zoomed in" naturally than gopro. Its all in your preference really