Pros
Booz Allen Hamilton is a challenge to master, but when that occurs, you can write your own ticket. The work is as diverse as any consulting firm but many of the employees are of exceptional caliber. Ther are not many 'slackers' at Booz Allen, they don't survive long and there is a heavy emphasis on being the 'best' you can be within your industry and attaining the right educational and professional credentials to support knowledge gained.
Cons
Some of the downsides include a fairly rigorous "chain of command" in terms of who is responsible for what and what perks may exist. Another is the whole company marketing approach which means that client relationships are handled a certain way and if you don't understand this process, it can take a long time to become successful.