Pros
Good if you're young and have no kids, or anything that will keep you from missing work. You get good med/dental/vision/life benefits as soon as you start working. The phone plan discounts aren't much of a perk because its monitored.
Cons
AT&T is the most unethical company I have ever worked for, working as a customer assistant for their Broadband Internet Service. They tack on more and more job duties to your position for so little pay. Your job performance can not be lacking or they will put you on an action plan (e.g. steps you will take to make monthly goal or you will not have a job). AT&T does not tolerate being late or absences. They don't care if you have kids or not. You will be required to work the needs of the business or you will not have a job. You cannot have a family/life and work there. If you are going to school they will not excuse you for anytime off. The environment can be very stressful, working long hours and being very micro-managed. It is a high-school atmosphere where people gossip and can not be trusted, even management. They don't care about their employees, you are dispensable!