Pros
Working among other talented people is great. Small company with a tight-knit group of workers.
Cons
Management isn't up to date on the state of the industry. They also tend to be very passive about seeking new clients and encouraging growth among employees. Strong tendency to play "favorites" with staff, lots of silly internal politics that accompany working for such a small company. No opportunities for advancement. No annual reviews. Very, very high turnover - I personally witnessed more than 10 people pass through one position during my time at ACG. Several ex-felons among staff. When the company is doing poorly, expect your hours and pay to be cut.