I've participated in many hackathons, AngelHack has been one of the better ones, that said don't be surprised if there is disorganization and confusion. They have been getting better and providing better food.
Primary reason to attend, working with sponsors. In the past AngleHack has been good at bringing good sponsors/api vendors so its a good opportunity to engage with SAAS, PAAS and APIs.
Its about hacking in a short period of time, so overall a fun environment. Also a good opportunity to connect with others, but don't expect to build a team for your idea, bring a team with developers if you expect to get something done.
Too early to say about their just launched accelerator.
(Their "Upvote us..." is lame, and not in the spirit of quality comments)
