Pros
Learning on the job... one year at PwC is worth 2-3 elsewhere. You really get to learn a lot about different industries, business processes, etc. The access you get to partners, CEOs, CIOs, and other upper level management (both internally and externally) can't be rivaled. You are also tossed into high stress situations where you need to make decisions very early on in your career. Training is great as is support in gaining additional accreditation- CISA, CPA, etc. PwC requires that you gain enough training credits per year that it's never been a problem for me to retain my CISA certification.
Cons
Work/life balance is often a struggle and you are usually faced with a choice- be rated highly or have a life... Some upper management are so incompetent that I wonder how they graduated HS, much less are tasked with coaching others. The worst part is that these bad apples- and they really are the majority- make life worse for the rest of us. Promotions and layoffs/terminations, in the past, seem to have been fair, however in these hard economic times, seem to be based mostly on business case. There have been cases where I've seen people get promoted, and I work with them and realize that they really are one-trick ponies who are great at that one big recurring client, but have no business acting in the role they've been promoted to.