Pros
They train and expose you to TCP/IP. You won't be certified but you'll learn a bunch of practical stuff: protocols, mail clients, browsers, remote session, port forwarding, PPP and some cool tools too. The most important thing you learn is how to troubleshoot. Noobs with a little effort can get a L1 job and then move on to make the fat coin somewhere else. My L2's were supportive and the schedule was flexible. Get to work at home.
Cons
The pay sucks! and you're asked to do a lot for little pay. You're busy often with back2back calls. The weird guy at work can be one of your L2's. Hanging up on customers because they curse is probably frowned upon. Impersonal in that you don't have work friends when you work at home. The metrics by which your calls are measured may be difficult for some. Once you get the hang of it (3-4mo.), you quickly get burned out.