Pros
You can really work on diffusing frustrated people because 95% of what you'll be doing is speaking with angry customers. I got very good at dealing with upset people. You also learn how to stretch a dollar because your pay will not change.
Cons
No real room to maneuver or grow. If you start out on the phones, you'll grow to the point where you hit a wall and can't progress any further. No additional pay will come with the added responsibilities you'll take on, either. The staff is also very gossip-driven, and if you're placed on a team with a supervisor that establishes clear favorites, you either suck up or they find a way to drum you out. My numbers were great until I was placed on one supervisor's team, then suddenly my numbers dropped and I was laid off.