Vantaggi
If you're legitimately interested in accounting, the Big 4 is the best way to start your career. You're immediately exposed to an array of clients and your ability to think and react quickly is greatly enhanced. Also, there are great exit opportunities once you make manager. Benefits are good, PTO is good, etc. KPMG is also great socially -- lots of young people make it a fun place to work.
Svantaggi
Busy season is busy season. If you're unlucky and busy season is extended for many months, your work-life balnce will not be so balanced. The work as an associate is not very thought-intensive, though you do gain responsibility quickly. The work also is not very rewarding -- you don't really change or create things, you just verify.