Pros
A lot of great people work here, and the flexibility of "unlimited" vacation is fantastic. There's a strong community vibe, which I love. Plus a stocked kitchen, a nap room (though have you tried sleeping on a hammock? It's not comfortable), and a new gym (I didn't get a chance to use it as it opened the week before I left, so I can't vouch for its quality).
Cons
Specific to working in Support: the position is sold as a jumping-off point from which you can get any job in the company, but in reality that's a very difficult leap to make -- even when you're working hard and networking well. It is absolutely a job where you can learn a lot, but in my experience other departments tend to be reluctant to hire from Support. If you do apply for positions elsewhere in the company, the process tends to be long, drawn-out, and confusing, with unhelpful feedback. It's easy to get burnt out in Support, particularly since management has begun cracking down on productivity metrics. In addition (this is an incredibly whiney complaint, but it should be said) it can feel like Support is the redheaded stepchild of the company. Other departments get showered with ski retreats and personalized Bose headphones, while Support gets a warm handshake and a pat on the back. Not to undervalue the back-pats; it's great to hear the execs tell you you're the most important department in the company -- it just would be a lot cooler if they actually treated you that way.