Vantaggi
The best things about Booz Allen are the opportunity to work with some really incredible people both on your team, and occasionally, on the client teams. There is also a lot of flexibility within the firm to get 'matrixed' across other teams, which really helps out with the networking side of things and to allow you to get the chance to work on some really different projects. Its also been my experience that the organization's heirarchy is relatively flat except for the ethereal plane where the partners dwell. I've definitely appreciated that level 4's and 5's have taken my thoughts, concerns, and work seriously even when I started out a couple years ago as just an undergraduate. At least at the junior levels, I've seen that the firm does recognize and reward merit and effort. They could do more, but I've had more success at Booz than my peers have at other places.
Svantaggi
Well, the pay is not always commensurate with what you see at other companies in this industry, that can be somewhat frustrating. Also, you do occasionally have to deal with managers who don't have any strategic vision or ability to communicate about the growth of the projects and the people on the contracts; by this I mean that I've seen several managers just continue to 'wait and see what shakes out' for nearly a year without making any moves to really show the client what it is we're capable of offering them. I wrote up a whitepaper on what we could do to help our client meet the next stages of their development, and it took a year for the boss to finally come to the conclusion that these challenges were in fact inevitable and that we'd not been prepared to capitalize on these facts.