Pros
The team is really incredible. Everyone is super intelligent and easy/fun to be around. Your coworkers will turn into your close friends and you'll have a blast at all of the events, happy hours, and offsites. The most rewarding part is how large of an impact you directly have on our community. You are never just creating products/features/fixes in a black box and not knowing the outcome. Everything you create gets released to millions of dedicated users and you'll hear from them in your inbox about what you are fixing and building. It's incredible to be able to have a positive impact on so many people day after day. The benefits are also outstanding and compensation is fair. Highly recommend!
Cons
If you are not driven this probably is not the place for you. There won't really be anyone breathing down you neck handing you projects/assignments/tickets. It's more like a startup where you go find work, get it done, and deliver. For myself, this is a pro. For others who prefer a more rigid structure, it may be perceived as a con.