Pros
I enjoy the team environment. Although we are moving away from the current team structure, there is always a 'gung-ho' teamwork atmosphere that I appreciate. The overall compensation package is quite nice, despite the mystery surrounding compensation at higher levels. The benefits, work-life balance, salary, etc all add up to a nice overall package. The experience you gain from working hands-on with clients and fellow staff is invaluable. The level of intelligence, work ethic, and morality of co-workers is second to none.
Cons
The unexplained "Booz Allen Way." There is very much a "jump in with both feet" and "sink or swim" (to mix metaphors) aspect in coming to BAH. I've heard countless times when making a suggestion or recommendation that "our culture" would in one way or another impede the execution of said idea. That being said, there are firm-sponsored ideas festivals and whatnot, but overall I'd say that until you figure out the nuance of the culture, it can be very difficult to become acclimatized. I have noticed that there is also a passive-aggressive nature to the culture. Nobody wants to say 'no' - rather, there is a 'qualified yes.' If you disagree with a point someone is making, they will move to then agree with you, but explain how you are wrong, gently. This is difficult to articulate. The assessment process leaves much to be desired. Specifically, it is an enormous time-sink and as mentioned by others has little bearing on salary increases and promotions (for Associates, at least). Rumors abound regarding minimum team size and new business value requirements to break down the wall to Sr. Associate, but it's hard to find the recipe for the secret sauce, unless you are somehow chosen. Finally, there is little day-to-day feedback on performance. I've heard this described as "364 days of pats on the back, with one day of slap in the face." That one day is the assessment, when everything comes out that could have been addressed throughout the year.