Pros
Almost unlimited career opportunities in terms of responsibility, relative autonomy, skill and knowledge development, leadership roles, speaking engagnements. Very well-organized with clear role differentiation and an effective hierarchy - you never need to wonder who to go to for what. You can earn respect based on your work without politics playing too big a role. Lots of schedule flexibility, especially as you become more senior but even for the junior folks.
Cons
Very difficult to have work-life balance due to an over-emphasis on metrics (billable hours, sales), resulting in long work hours. Even the most efficient workers work a lot of hours. If you don't fit into one of the neat boxes in terms of your expertise or background, it can be difficult to thrive. Top management is so engrossed in the numbers (profit) that they don't understand the day to day, and they are more focused on commodity selling than what our clients want -- consulting advice and knowledge over a long term relationship.