Pros
You get to work with highly intelligent people to solve the latest problems that face the Internet. Massive amounts of data passes through the network, hackers launch complex attacks, and global politics actually effect you. It's a truly impressive place to work. And you're ultimate goal is to make the Internet a better place. That's just awesome. The office is gorgeous and loaded with great amenities to make your work experience comfortable. There's a great work/life balance, but it is still a start up.
Cons
You could stand to make more money. With massive growth, it's hard to find who has the information you need, which means it can sometimes be a real challenge to complete a task. But everyone is nice enough that it's not a terribly dreadful journey.