Pros
Lots of flexibility to choose projects and propose improvements. Fast paced, challenging environment. Progressive company that values it's employees. Company has driven improvements in managerial training and personal development. They provide great profit sharing (usually 20% of your base pay depending on the year) and bonuses.
Cons
HR is under supported and doesn't seem to truly care about the employees. In my latest role, I didn't meet my HR rep for over a year-and-a-half. Because of this, a bad boss or co-worker could ruin your experience here. The building you work in will also have a huge determination in the quality of your experience. Many office spaces are severely outdated and truly depressing to work in and the managerial culture is very different from building to building.