Pros
You are treated by management as if your opinion really matters, regardless of your position in the firm. This is amazing! The people are (mostly) fantastic. I have worked at some terrific places and nowhere has been as friendly and intelligent. They want you to succeed within the company. If you're the best performer in your area, you can be sure that there is a big bonus and/or a promotion coming up. Work-life ballance is great! I very rarely have to spend more than 40 hours a week to get my work done and some weeks spend a little less. Benefits, time off, management, etc, etc - pretty clearly I love my job.
Cons
As is the case anywhere there can be some office politics, but no more here than anywhere. They do protect tenure a little too much in my opinion. While people aren't getting promoted for having been around forever, they somewhat exempt from 'real' performance review.