The military basically forces you to take direct deposit (not doing so would be such a pain in the ass that the option effectively doesn't exist) and that is a big part of why USAA is such a successful corporation. USAA takes direct deposit just like every other bank in the world. In fact, setting up a direct deposit account is a requirement to take that career starter loan (unless things have changed since I got mine in 02). USAA, or any bank for that matter, wants you to set up direct deposit.
While you don't get paid until the 1st or the 15th of the month, DFAS (basically the DoD accounting firm) actually sends direct deposits to your bank about a week to 4 days prior. USAA holds that money until it is disbursed to your account and can earn interest on your money before it is in your account, where if you were to deposit a payroll check, the funds would be available to earn interest for you immediately. No, you don't earn much interest in 4 days, but multiply that by a million customers all getting paid on the same day, twice a month and it definitely aids the bottom line - the whole "time value of money" thing for all those econ majors out there...okay, there probably aren't a lot of econ majors here. It doesn't really matter of course, because you are going to get paid on the 1st and the 15th one way or the other.
That being said - USAA is almost a requirement for deploying military personnel - deposit@home is how I have been cash everything an has effectively replaced any need for a bank branch, and their web billpay is an easy way to manage bills while you are overseas. The reimburse your account for any fees associated with using an ATM (HUGE overseas). Their rewards program for credit cards is awesome and they have low CC rates - you should probably only use credit cards overseas for protection and the best exchange rate anyway. The customer service is second to none (just press 0 when you call and go right to a rep) and their insurance is the best in the business although slightly more expensive than other options.
The weak link in the chain is probably there investment side, but they do have a good Precious Metals fund that I invest in which has been posting up to 23% gains for the last few years during a down market.
Navy Federal is a good option if you want a branch and usually has better loan terms for autos and whatnot - which is why I maintain an account with them. They aren't as savvy on the internet though, and their website sucks (last time I checked). I don't know if there is any "Army Federal" or something like that, but there may be.