Pros
Solid base of work. Smart junior staff. Fun colleagues with some nice corporate events (Holiday parties, picnics, Chinese New Year, etc). Above average compensation for development field. Great travel opportunities. If you have the right boss you can be put in charge of significant parts of projects. Friends have gone on long terms assignments to the field after only a short time in DC.
Cons
Government contractor. Beholden to US Government, which means we're beholden to swings in funding. They recently laid some people off because of lost contracts. Support divisions are hit or miss. Benefits are bad compared to peer companies (401k is a joke). Junior staff doesn't know what management is thinking. If you have the wrong boss you will type numbers in excel all day.