Hero2 is the OS in question as to how easy it is. My gripe with GP is that they can't seem to release it all in one package. So, you buy the camera for $300, then add the $100 wifi (which doesn't work) and you wind up with a bulky package for $400. If you read the reviews on the wifi, GP had been delaying the release of that app for months with no end in sight.
Compare that with the sony, which comes in at $279 for all of it, and it shoots more fps than either GP or Contour. I think the mount system for Sony sucks, but that's just a matter of aftermarket catching up. The gotcha on the Sony is the MP for stills, which I think is around 3. At least the GP has MP around 11 for stills.
This is where I think the Best Buy return policy is worth it's weight in gold. Sure I could buy one from amazon for less, but BB let's me take home 2 of them to compare and play with. I'm a pretty careful guy, so the risk of damaging one is pretty small. I don't think BB is going to carry contour, but REI does. And REI's policy is pretty much the same.