Ventajas
Really smart CEO, very down to earth, no attitude, flat company, he even cleans dishes and motivates everybody. He makes sure the team is very involved in diff aspect of the company, all the way to sharing company hiring plan, financials, board meeting presentations, etc. I've never been inspired more and challenged more in my career (post grad school) and there are zero voluntary turnover with the company. Great, open and inspiring culture. Our engineering team has a strong sense of pride and ownership for being here and working on a tough product to build.
Desventajas
OK benefits, though it's getting better (just signed up for Blue Cross). Long hours, occasional late nights. The team expects a lot from you (though the founders work more than anybody) - and overall, feel that being a "hardcore" start-up (like those in SF) is a good thing.