Pros
If you desire to work at a place where advancement and education are not valued, then AT&T is the right place for you. You can work here for 35 years on cruise control, just kiss the right tail and you'll be fine. That's assuming that your director, ED, and VP don't screw enough stuff up to get everyone surplused. So if you are a yes man, who had no desire to get additional education and you don't want to get promotoed, then this is a good place to work.
Cons
I worked at this company for several years and had several years of "far exceeds expectations" on my yearly appraisial. I never got promoted despite many attempts to do so. As a manager you have no authority to make decisions. All decisions have to go through about 15 layers of red-tape to get approved. Senior managment is greedy and lines their pockets with 8 and 9 figure salaries, bonus, options, etc. while they continue to take bonus money and raises away from lower and middle management. Be prepared to purchase your own supplies as AT&T will not provide them for budget reasons. Morale is extremely low and when I left, I had dozens of colleagues ask me to keep their contact information in case there were opportunities at my new company. There is a sense of sadness when you walk into many of the offices as most people really don't want to be there. Don't fall for this line from managment..."This job is the right opportunity for you and you'll get exposure to the right people who will help you get the promotion you deserve and have proven in your skills and work habits." I heard that several times in many different positions and when the opportunties to go up a level opened up, I'd get this line..."Well, the budget is really tight right now and I really can't promote someone right now and I'm going to have to make this a lateral move." That was a common occurance. Backstabbing to get ahead is commonplace.