Pros
KPMG is a true meritocracy. You are generally judged on the work that you do. There is little politics. KPMG provides employees with the opportunity to grow that is rare. Exposure to clients provides exceptional experience. You work with extremely talented and dedicated professionals. You receive the view into your clients business that is rare. You will see a picture that only executives of the company do. You get to look at their business at a high level and get down into the details as well.
Cons
Hours are, of course, really bad. If you get the on a bad client if may be difficult to get off of the client without be regarded as complainer. Your immediate supervisor has significant say over your performance evaluation; if you have supervisor who is not in your corner you may not be given a fair evaluation. It is very hierarchical, by necessity, but it has it downfalls.