II on Friday, complete end of July (ORM LM 75, no prior service). SO STOKED. Uhm, what's the deal with army "filling up"? If I put army as my #1, would that hurt my competitiveness/chances of acceptance? Also, apart from my own googling, is there somewhere I can find more in-depth information about the branches?
At this point, it's likely that the entire class has filled, which means all the branches are technically "filled up." However, that does not mean that you cannot get accepted. Essentially, after your interview your application will be reviewed by the committee. You could essentially have a few things happen:
1. you get straight up accepted and offered a seat in the class.
2. you get accepted, but you are put on the priority waitlist to wait for a seat to open when people start withdrawing or getting DQed en masse. The withdraws really start happening after April 30, but they can happen in March too when Harvard releases its decisions.
3. you get put on the alternate list, which means you didn't get rejected, but you'll have to wait until everyone from the priority waitlist is offered a seat before they get to you
4. you get rejected
So even though the class is probably "full" at this point (I don't know if it is, officially, but it usually is before now, so I'm guessing it is), you can still get accepted. It is hard to tell whether putting Army will make it less likely for you to get in if you end up in number 2 or 3. Last year, all 3 branches went into their alternate lists. The Army has the most spots, so if you end up on the alternate list that means they have to go through more people to get to you.
But honestly, I wouldn't pick a branch based on that. List them the way you actually prefer them. The military can be difficult enough without being in a branch you really don't like.
As for learning more about them, you could always request the host program and ask to be placed with an Army student. If you have Navy questions, I can help you there.