Pros
It's refreshing to work for a company where the mission statement and values are more than just words on the wall. USAA actually seems to care about its members, and regularly puts member satisfaction above pure profits. As far as software development goes, USAA is a great place to work. Most of the developers here are a pleasure to work with. Middle managers usually come from technical backgrounds and actually understand the teams they're managing. The work environment, while maybe not shorts, flip-flops, and margarita machines, has moved a long way from the suits and ties of the 80s, and is actually pretty fun - especially the new Plano office.
Cons
Overall, USAA is a large company and a conservative company. Between the two of these, there is a definite lag in adoption of new technologies. The Plano office has a very open environment, which is great for collaboration but less than ideal for concentration.