My son is currently a West Point Prep at NMMI. I can tell you a few things about the place from a Mom's point of view.
Good things I have heard from my son:
1) Academics - He likes the professors and says they are willing to help before or after class if you have questions. Classes are small too. He feels that he is getting an excellent academic preperation for West Point.
2) Military school environment - When you go to your academy you will be used to shining shoes, putting together a uniform, marching in formation, etc.
3) Friendships - He has made some really good friends among the prep cadets, not just West Point preps, all the preps. All preps basically take the same classes so they get to know each other pretty well.
4) Time management - You learn to manage your time better so you can get everything done in the time you have.
Complaints I have heard from my son:
1) Food - he says the food in the mess hall sucks. I guess it just depends on what you like, some people like the food.
2) Leadership - there are some issues with leadership at the school. Cadets in leadership positions not doing what they are supposed to be doing or just not caring about the rules. Inconsistancy in applying the rules to all cadets.
I have heard from other cadets that went to NMMI that it does give you an excellent academic foundation for the academy. One former cadet that graduated from USMA last year told me that he doesn't think he would have made it through without his year at NMMI.
My son is away from NMMI this weekend on a band trip to Disneyland, when he gets back I'll see if I can get him or some other preps to logon and tell you more. They don't have a lot of time to be on the internet but I'll see what I can do.
If you have any specfic questions I'll do my best to answer them.