Pros
The culture and the clients leave you feeling that you are making a difference in the world. Interesting challenges, a variety of clients and the ability to be personally involved in the work we were doing made it easy to get up for work in the morning.
A small, boutique agency means everyone knows your name, and we were really all extended family.
Cons
A small boutique agency sometimes means that it's harder to expand or increase responsibilities than it might be in a bigger environment.