Vantaggi
Friendly atmosphere, lots of young people, good understanding of work/life balance. Good name recognition of the company. Excellent reputation with clients. Direct engagement with clients, and a lot of responsibility, relatively early in career. In general you learn a lot in your first 2-3 years, but after that it just seems like more of the same, unless you get tapped to help lead a foreign office or get moved into another role/division within the larger company.
Svantaggi
Crappy 401k matching (also requires 3 years of service to vest). Salary freeze in effect all year so far; talk of "reevaluation" come 2010, but no firm commitments on lifting it. Relatively crappy office locations, with the exception of the HQ in NYC and maybe some of the european offices.