Pros
AT&T has very many talented, driven people. The IT shop has a standard process and toolset so it makes it easier to communcate across organizations and have successful implementations. Pay and benefits are very competitive. Generally, management is good at sharing information, although one can feel inundated weeding through all the communications.
Cons
There is a ton of change and work to do, along with aggressive timelines, due to the competitive telecom environment. Employees are asked to be advocates for the company by promoting products, although they are compensated for referrals. There are still plenty of customers who've had bad service experiences so sometimes this gets uncomfortable when talking to friends and family. Non-union (management) employees who normally have desk jobs must spend many hours training to fill in on phone repair and service rep jobs in case the union strikes. This happens every four years when a new union contract must be negotiated. With regard to work life balance, the company does not promote telecommuting and has few professionals who work part-time, although some is allowed.