Pros
The name recognition on your resume really allows you to go to many other companies in the future if you desire to. Many of the people i know did not work here for very long because the demanding hours, but they were able to transfer companies when they wanted to get out of the industry. The Big 4 are all interchangeable, it all depends on the office location and the peers you happen to work with on an Audit. If you want to start your career off by really testing your endurance and living to talk about it, join PWC.
Cons
The burden of having long hours without overtime in the United States. It's a bit unfair, but the generally accepted standard in the accounting industries. Sometimes I have to cancel prior engagements, such as dinner, when it gets busy. You start to notice that you're aging a bit more than your friends who aren't working the strenuous hours that you must endure when it gets really busy. Personally, I'm not into working 15+ hours a day, but it has happened when deadlines needed to be met. I'm only a first year, so I anticipate that responsibilities are going to only grow.