I have a 3G one and get great battery life like 6 hours. What I have noticed though is while in standby mode it still drains a fair chunk.
Game wise you need LBP Vita as well as a bunch of PSN games like Mutant Blobs Attack. If you like a franchise then defiantly go with the Vita game in that series. Heck even Resistance and COD are fun if you're into FPS games.