Pros
Discounts on wireless, TV and internet are nice. You can also pretty much apply for any position within the company and land it, even if you have zero experience in that area. In fact, the less experience you have in certain fields, the better off you are as a candidate since AT&T rarely follows anything like industry standards (other than Agile or what they think is Agile). I guess that's a pro?
Cons
One of the worst corporate cultures I have ever seen. Corruption is off the charts, rampant backstabbing whenever an opportunity presents itself, undermining of efforts through the withholding of information needed to complete tasks, work silos, and the list goes on and on. Every company has politics, but AT&T is on a whole different level. There is also an incredibly unfair "country club" culture at work in Atlanta, with hostile groups that will box you out if they don't like you...and they don't like anyone that doesn't fall in line with their way of doing things. And God help you if you're in a time zone other than Eastern, because they will treat you like a nobody, and will make it very difficult for you to complete your work. Video subscribers are churning more than a Land O'Lakes butter factory. And it's only getting worse. The DIRECTV brand has been tarnished. The WarnerMedia acquisition has created severe debt problems for AT&T, and the company is promising Wall Street a rapid "pay down," and one of the ways they plan on doing that is through massive layoffs, which are referred to as surplus events internally. A layoff culture, like AT&T's, creates a workforce that is more conflict than collaboration, and right now, I would describe the workforce in some organizations as "all-out war."