Pros
Market or better pay, good benefits, and open feeling office space. More than most company fun events. You usually feel very engaged with peers, the management and clients. Generally you will be thanked for good work and told you are doing well. Whenever you have to work late evenings, you get to order out free food.
Cons
You have to work hard there, sometimes long days and weekends - which could be rewarding both monetarily and for work experience.