Pros
Our cycles are super fast, we do releases almost evert day and iterate on product and learn very quickly. Since we're a small team, there's no politics and your responsibilities are as broad as you can handle. The benefits are fantastic (great health, dental, vision, 401K contribution etc). The team is fun and easy going, although we all work very hard. The hours are very flexible (many of us have kids so it's completely normal to take an afternoon off to go to a pre-school event).
Cons
If you're used to (and like) working at a large company, this probably isn't the place for you. We're going after a very big opportunity so there's no time to waste. We don't have an extensive training program; you're pretty much expected to learn on the job. Although the hours are flexible, we all work very hard. But good news is it doesn't feel like a job - rather a common cause we're all working towards.