Pros
Everybody working towards the same goal together is an inspiring thing. The company is at almost 50 people and still has the environment of a 20 person startup. Of course, Free Food, Free benefits, and lots of other perks don't hurt. The CEO greets the entire team at the beginning of every week with a stand up, and concludes the week with an all hands. His desk is right in the middle of the office, too, so you can approach him at any time. Team leaders are always open to have one on ones and offer advice or feedback if you need it.
Cons
Be prepared for a very transparent culture. It works both ways. Feedback is given directly and objectively in both directions, and it can be hard for some people to handle. The end result is very positive however, as everyone feels comfortable being open with each other.