Pros
Facebook is a rapidly growing company where you can work on digital products (and the infrastructure that support them) that impact a billion people around the world. The company culture is richer and uplifted more-so than any other company I've worked at (including Microsoft, IBM, and NYT). We're encouraged to take control of and have ownership over our work, micro-management is micro-managed out and big-impact work is rewarded (even—no especially—if it's not sexy). There are few places in the world which provide the hat-trick of being an exciting place to work, provide freedom to work on what you want, and provide social and cultural impact to a significant portion of global humanity.
Cons
The biggest downside is the double-edged sword of Facebook's culture. It's easy to get lost in the whirlwind of cool stuff, great perks and exciting smart people and forget to get something done. For those cranking away, the intentional self-exploration (hackathons, etc) can result in the occasional duplicated work or dead-ends. You can't say we won't take risks and try new things, instead you could say this might happen a little too much. Also, Facebook is a pretty constant target of the media for both good and bad news. This can be a bit trying when you just want to get your job done and your friends and family are bugging you about the latest features added (or not added).
