The nice thing about the GoPro is that they are so popular that you can get tons of accessories for them, also a better chance of snagging a good used Go-Pro on craigslist or eBay for a nice discount.
That being said, i'm sure the contour has a bike and helmet mounts as well.
The new GoPro allows you to control it and review videos from your smart phone. I have an older one, which has been great to me over the years, but a recent ski trip, i saw the newer thinner lighter version and it was nice too, but did not make me want an upgrade.