Hero 3 is still quite premium priced as it’s so new- it’s the one to get but I’d wait til the price drops, or try and benefit from people replacing older versions with 3s. (my 2 will be up for sale as soon as the Black edition 3 comes down a bit)
Warranty… I’ve had 2 Gopros, both were absolutely spot on. Replacement parts are available and they warrantied a broken mounting without any fuss. So wouldn’t really concern me but then, the new one’s less proven.
For mtb- you want the chest mount, it’s pretty much compulsory. I’ve bought some extra sticky mounts (shoes, I call em) as I wanted to put one permanently on my main helmets (2 on the fullface), and used some others for stuff like modding a Gorrilapod (*-1). The seatpost and rollcage mounts can add extra options for variety but aren’t essential (*-2)
Oh, I also modified a Gopro arm into a mount for my lights- since there’s a shoe on all my helmets anyway. Worth it for me.
(*-1) Or other small tripody thing. Just attach the Gopro “foot” by whatever means you choose to the top of it, so you can quickly attach teh camera to it. Good for “up tree” shots, ridebys etc. Videos of all POV footage are pretty dull no matter how good the riding and footage is, breaking out to static shots a couple of times per vid makes a huge difference. And the faster you can do it, the better.
(*-2) The bar/seatpost mounts aren’t quick release- see above, basically the longer and fiddlier it is to move the camera, the less you’ll do it. But you can stick the sticky shoes to your frame or stem if they’re a suitable shape.
