Also note that their newest line of cameras, the HERO3+ (plus) are only smaller in size and lighter in weight. As of now, the Black Edition for both Hero3 and Hero3+ are only a few dollars different in terms of price, so go for the plus! And now that the HERO4's are out, check the prices of previous versions as they'll be dropping slowly. Unless of course you want the newest of the new, check out their HERO4!
Although obvious, I put this here first because this is one of the most important factors when purchasing your camera. The HERO3 has three editions (white, silver and black), ranging from $199 - $399 (prices continue to drop annually as newer versions are released -- we'll keep you updated on those). The HERO2's are at the bottom of this gap, but aren't as "new" and lack some features the 3's have (they're discontinued at this point but can be found on the net here and there).