Smart, capable and talented employees. Funny and entertaining as well. Relaxed work environment, not too serious. One of the interview questions was "Star Wars or Star Trek?" (note: the office is full of Star Wars stuff).
Cons
No one was excited about the work they were doing, or the products they were developing. I mean, it would be hard to given what the company does, but you could tell there was a definite lack of enthusiasm throughout the whole dev team.