Pros
The benefits are great and there are several diverse opportunities for growth or even a new job. Compared to other companies of a similar size, the benefits are top notch... retirement, health, work/life balance, etc. The headquarters is like a small city, with restaurants, gyms, Starbucks, stores, and a pharmacy inside. There's also childcare thru the company (not on site, but across the street). No matter what you're interested in doing, the job probably exists at USAA, and if you want to change jobs to something entirely different, that's possible (though not as easy as just switching whenever you'd like). Additional perks come from the location - San Antonio is a great place to live. Also, the mission of the company is probably the best you could hope for - serving the US military community.
Cons
It's a large company but some of the process and people seem straight out of a small company setting. Some management can be less than inspiring, and rarely, downright incompetent. The average age of employees is fairly high, but that speaks to the lower turnover than average and the fairly high competence level of co-workers (compared to other companies). The company preaches openness to change, but actually accepting and acting on change suggestions is still hard for the leadership to grasp in most cases.