My son has both PenFed and USAA; one for banking, the latter for insurance. He also retained his local credit union account as it is linked to our family account.
If you don't need the physical presence of an actual bank building, then USAA is fine. My family has been a part of USAA since the 70s and we have no complaints; great service and no problems at all. But USAA does not have my banking. USAA has great customer service by phone or web, and of course all account info is accessible via web or phone. They just don't have a physical presence.
Without an actual physical presence, however, it's hard to offer other services - like a safe deposit box, getting a cashiers check quickly, or getting a large amount of cash to name a few.
Since both were essentially free accounts, my son setup accounts at both. I've set things up so that I can transfer money from my accounts to his, and also take care of insurance matters. I did this for both USAA and for PenFed.
As noted, just outside the Thayer gate is the PenFed credit union, and a USAA insurance office.
And of course, there is lots of info at their respective websites - plenty of info to compare. The websites however don't identify all the benefits offered to new cadets, so a phone call or personal visit might be beneficial.