As a new owner of a GoPro (3 months) I have to say that I am not as impressed as I thought I would be.
The battery doesn't last nearly long enough for it to be properly useful. I don't have extra cash to dump on overpriced spare battery packs and a million different accessories. The GoPro doesn't even have a standard tripod mount. You have to buy that separately. Everything is another accessory, another feature, more money.
It also takes inordinately long to charge because it has to charge via the computer, gets ridiculously hot during both use and charging, and the mounting/casings/straps and everything are laborous and annoying to open/close/use.
I'm rather disappointed. I would get rid of the thing in a heartbeat in favour of something else insteadSomething I would actually use.
That's not really a fair comment on the GOPRO. It's like buying an iPhone and complaining that the cover is extra. If you buy the branded Apple accessories, you pay a massive premium.
Same goes for the GOPRO.
However, if you buy generic mounts and batteries via eBay, focalprice and dealxtreme dealxtreme, you'll find decent accessories at a reasonable price.