The interview process itself was not bad. I had one interview on campus and another at their headquarters in San Antonio. They paid for travel expenses and had a number of tours and informational sessions along with the three on-site interviews. This process was fine and it was nice to see the campus and tour it, although I think some of the events lasted a bit too long.
However, the people who were given as contact points for questions after the on-site interview were very unprofessional. I had another offer come in and inquired to the status of my application and was told that USAA knew they wanted to make me an offer but they needed a bit longer to get things together. I was told I would hear from them no later than two business days. Two weeks later, I had not heard anything and no one had contacted me or returned my emails/call (one or two emails and one call, so nothing crazy).
Finally, I hear from them about three weeks after they had said I would in a generic auto-generated rejection email. I found it incredibly unprofessional that they "verbally" gave me an offer only to end up sending me a rejection letter over three weeks after the date they gave me.