This is my first AX, I also got the room with a military discount. All in all the price wasn't bad and I was looking at being close to the Con. I would love a rent-a-cop try being an asshole to people because he doesn't like different, he would hate life. I plan on just ordering out for the most part and have a night or two for a good restaurant and wont be needing a car.
I will be cosplaying for 1 or 2 days, but my main thing will be photography and exploring.
Most of the hotel's security was very good, and I didn't have any problems with them. It's mainly Mark Blackburn that you have to watch out for. That man has a huge super big ego, and talks down to you. (Especially if you are wearing a costume.) Hopefully you won't have to encounter him.
There are also cheap eats nearby that's within a short walking distance. There's a subway, and a IHOP restaurant nearby as well. (I would highly recommend the IHOP. ) Avoid the nearby Denny's because both the food & service is terrible. (And it's always crowded at night.)
There are a lot of restaurants around the hotel in the LA Live area, but keep in mind that they aren't also cheap.
Also, don't forget to peace bond your weapons at AX when you are cosplaying so you won't constantly be stopped by AX staffers or security. (Airsoft weapons are not allowed.)
At certain times of the day, the con will be packed with people bumper to bumper. (Especially on Saturday.)
Also, try not to walk around by yourself at 3 a.m. if you can help it. While it is usually safe in the day,and evening, I wouldn't recommend hanging around very, very late at night or the wee hours of the morning by yourself. (It is downtown LA after all.)
It may also get really hot in the day, so be sure to bring bottled water with you. (There was one time when it reached over 100 degrees one time at AX.)
A few other points about the J.W. Marriott. Many of the rooms have only shower stalls in the restroom, and they don't have bathtubs. When you request a room, and you want a more quiet room, try to request one that is NOT close to the elevators. (It can get rather noisy when it's crowded during peak hours, especially if you are close to the elevators.)
Sometimes when the crowds are at their peak, it takes several minutes to access the elevators. There is also a movie theatre right across from the street from the hotel.
The hotel also shares the same building with the Ritz Carlton. They have a separate entrance & exit from the hotel though. (But you can use the Ritz Carlton entrance to access the J.W. Marriott.)
BTW, you mentioned that you are in the service. If I may ask, which branch are you in?