Pros
Depending on the project and team lead/manager, there can be very good mentoring from the senior staff. Most personnel at the director level are very good mentors and excellent subject matter experts. Most co-workers are a pleasure to be around during work and after work hours.
Cons
Long hours depending on the project. If you end up working on a large engagement on a client site, there will be virtually no work/life balance since you will be asked to work long hours. More than likely, you'll end up loosing your vacation time. It takes several years before most people see their first promotion (of course there are the exceptions where people are promoted within 4-6 years). Yearly raises can be given before receiving yearly performance reviews.