Pros
Booz Allen gives you the opportunity to tailor your own career without someone saying you can't. There are plenty of positions available for different clients and due to the company's "matrixed" structure, you can work anywhere, for any client while remaining on the same team. If you don't like your team, you can switch teams. To excel, you are expected to work within the competencies of the next level. For me, I started as a Consultant (L-1) even though I had 5 years previous experience in the field. By my first year, I was able to be promoted with a substantial pay increase (part of this was due to getting two additional professional certs) and increase in PTO days. BAH lays quite a bit of importance in its ethics. "Ethics First" is their program, and its the cornerstone of how the company conducts business. Honestly, coming from a much larger company to BAH was a breath of fresh air because of this and that the company does seem to really care about it's employees.
Company has great benefits and their ECAP program (basically your 401k) ensures that after your first year, the company contributes 10% of your salary to your retirement fund automatically each year. You can contribute as much as you want, so this can help you build up a retirement fund fairly quickly. Of course, it takes you 6 years to become fully vested, and if you leave before then, you lose all the contributions the company has made to your ECAP. Not too bad of a deal when you get down to it.
Overall, I enjoy working for Booz Allen Hamilton, and recommend it for anyone who is looking to break away from larger company that doesn't put much emphasis on employee satisfaction.
Cons
PTO days are your vacation days as well as your sick days. 16 days to start off with in your first year. Not the worst deal, but I was used to having separate sick leave and vacation leave in the past.
Depending on what team you are with, you can have a totally different Booz Allen experience. Some teams are better than others because of management and funding; so there have been cases where someone gets hired on and within 3 months they are gone because they had a "horrible" experience. But one can say this about any company really. Personally, I switched teams because I wanted to expand my experience a bit with a wider variety of clients.