Good place to build relationships, and grow professionally, if you can handle the challenging long term prospects.
Pros
PwC is all about relationships. It is a great place to learn how to influence without authority, and to see the real value of such a skill. Only people who are able to influence seem to be able to get anything done. Another big plus is simply the experience you get working for such a big firm. There are a lot of resources at your disposal to learn more and grow yourself professionally. You get to see a lot of good processes in practice, and there are many very sharp people working at PwC. The firm seems to be fairly well attuned to the marketplace, with a good eye on the future.
Cons
Inconsistent leadership can be a struggle. The performance review process is hit or miss. As with most places - the best reasons have a flip side to the coin. Since relationships are such a big part of the job, building good relationships with the right people can do wonders for your career regardless of your real performance in your day to day tasks. This can be challenging for people that do great work but don't relish the art of blowing one's own horn or kissing a lot of you know what to get ahead. This does not appear to be the rule, but happens enough that it remains a rather obvious fact of life.