Pros
The company pays reasonably well if you enjoy fighting corporate political battles. If you get in the right group, you can also remain hidden and work on your own projects without much interference.
Cons
I worked at Bell Labs for half a decade, what once was one of the innovation centers in the US. No more. The current leadership of AT&T (which is really SBC) gives lip service to innovation while laying off the scientists literally responsible for the Internet today. I did not witness anyone working on interesting software projects or research problems at AT&T today. You will only be happy if you enjoy helping accountants perform more cost cutting and legal saber rattling. This assessment may seem hyperbolic, and there are corners of the company that are still fighting to do good work, but I speak from experience. I've witnessed senior scientists humiliated, the careers of young software engineers and researchers wasted on trivial work, and front line customer servive reps told to screw customers to save money. The culture of the company is in decline and the best people --- some of whom gave their entire careers for the old AT&T --- have already left with great sadness.
