I borrowed a GoPro Hero2 the other weekend for some street shooting.
It is a very fun little camera if you like fisheye lenses.
Supposedly the Hero3+ has infinitely better high ISO performance, which sounds reasonable because the 2 has pretty bad noise - pretty much anywhere but base ISO has obvious noise. Otherwise it is wonderful. ZERO AF lag. stupid-high frame rate (10FPS@11mp, 30FPS@12mp for the 3+) and a big fat fisheye lens. So much fun. Really tempted to get a 3+
Click through for a few more pics.