Be prepared to work hard & figure out the ropes yourself in a highly political environment.
Pros
Great professional development opportunities. Opportunity to work with very talented, intelligent people from all over the world. Opportunity to grow a professional network. Potential to work with diverse clients. Proven personal reputation leads to greater flexibility in terms of where you work from. Company takes ethical and legal policies extremely seriously. Innovation is still alive and well at the firm.
Cons
Work / Life balance is a myth and burnout is the norm. Expect to work nights and weekends for the sake of business development. Bringing in new business is essential to getting promoted and is central to the company culture. You won't make as much money as other consulting firms. Intra-company politics play highly into every decision made. Lack of transparency from leadership about company's strategic vision. Executive communications cryptic and this permeates down through lower management levels. Job security is a myth. Increasingly an "up or out" culture.