Pros
Absolutely awesome community where merit is recognized and rewarded. There's a pervasive culture of ownership and responsibility which makes the job rewarding and fun. Plus, they're one of the more well-oiled machines I've ever worked at. Very few political issues, and a general atmosphere of camaraderie amongst the development team. You'll work on a dedicated team, with clear goals and clear deliverables. Having worked at a few places in various capacities, that is a godsend that is much rarer than it should be.
Cons
Pay could be better, as it's very difficult to hit market rate commeasurate with skillset. There are a few people that are holdovers from the early days in the director-level positions (when I last worked there) that seem to be very assured of their superiority, but even that was getting better by the time I left. I only left the job due to location concerns (they're far out in the burbs!) and a more competitive salary. However, I was ready to come back after four months at the new job, I missed it so much.