Pros
Lots of flexibility. You are given a lot of freedom - you just need to manage your time wisely and if you do your job, its a very easy place to work. No micro-managing. Many employees have been here over 20 years, and a few have returned after other opportunities arose. A "casual, family-like" environment. Pay is above average and compatible with much larger firms.
Cons
Not a lot of mentoring for very junior employees; but there are always team members accessible and willing to help out.