Pros
There is plenty of room to move up or even to different departments. Opportunities are often available to transfer to another department (move between client-facing, audit, analysis, and technical teams) or to take on additional responsibility (within teams/departments, within accounts, or into management). This allows employees lots of opportunity to develop and grow. There is also great work-life balance. With regular "9-5" hours, I always have my evenings and weekends free. I have a laptop but have never had to take it home to work after hours. There is also a casual dress policy, and going to work in t-shirts and jeans isn't the most important part of a job, but it is certainly an enjoyed benefit.
Cons
Because it's a small company, many of processes are not yet standardized, as they are continually being developed. I like this as it gives freedom to develop best practices and gives me autonomy within my position. However, this is not for everyone and I have seen this be a struggling point for some who thrive under additional structure.