Pros
The people at Booz Allen are some of the best you'll work with anywhere--bright, motivated, and highly professional. It remains a great place for entry-level professionals coming out of college or graduate degree programs, as their labor rates are lower so they will have an easier time finding projects and gaining exposure to career advancement opportunities.
Cons
As others have acknowledged, the corporate culture has distinctly changed. "Billability" has become the lowest common denominator for determining employee value; upon contract end, you have a slim margin of time--sometimes days--before lack-of-work (LOW) notice. Although employees are expected to seek out their own opportunities, there is very little guidance or support to help match employees to open opportunities, and the Resource Management system intended to perform this function is understaffed. Even when securely on a contract, this emphasis on billable targets impedes career development as it encourages staff to stay put in minimal-growth opportunities for the sake of job security. Individual experiences vary significantly, however, because there is wide disparity in how teams manage their budgets and staff. It seems that a team's leadership has free reign to determine its own LOW policy and make other significant decisions impacting staff without Firm-wide guidance. Such leadership decisions tended to feel reactive rather than proactive and were often poorly communicated to staff.