Pros
You get to serve the greatest military in the world who often already LOVE the company, meet and work with great people, learn from those at the top of their game. Working for USAA is like getting an MBA in your field and PhD in the power of corporate culture. You have access to incredible amenities, special events and a chance to work harder than you've probably ever worked, which is so rewarding in and of itself.
Cons
It's a hundred billion dollar enterprise comprised of many, many multimillion dollar companies. So naturally, and unfortunately, politics rules all. And competition is unquestionably fierce. People will attempt to destroy your dreams; USAA is not immune to evil. If you're a threat to someone in power, or are a risk for undermining the culture (read: ask questions/express dissenting opinions) you will be targeted for termination, period. Unreasonable expectations of the customer service reps in terms of time management, procedural execution. Constant shifting of the sometimes inscrutable goal posts. Minimal oversight of managerial interpersonal behavior, therefore a prescription for abusive behavior. This list could go on, but I think you're getting the idea. Although there's usually no tangible product, and the doors and floors are golden, it's a veritable sweat shop, not unlike most customer service call center environments.