I'll throw out what I know and what I believe to be true, given that I have been accepted for next year's entering class and am currently a military officer.
I know several now-, and former-students and can say almost without exception that they very much enjoy the school and feel they are getting a great education. For the most part classes and meetings are mandatory since they're paying you to be there. However in-lecture time isn't that much and there's plenty of time for studying. I'd say an average MS1 week is one or two full days (0730-1600) and the rest maybe just mornings or a lab in the afternoon. There are some military-type training classes and meetings but not so much as to be a nuisance.
The curriculum is largely traditional with some clinical exposure and military-specific (tropical medicine, combat casualty, etc) stuff thrown in. Their Step 1 and Step 2 scores are well above the national mean.
The question about an IM residency is a little complicated. Depending on the service you may have to complete PGY-1 then serve as general medical officer for a year or two before competing for a residency (this is mostly a Navy thing, the Army and Air Force are doing away with GMO's as I understand). However, it is possible, even in the Navy to go straight through residency after graduation depending on needs of the service, your grades, AOA, USMLE scores, your experience, etc.
Having said all that, I would encourage you to contact the school and ask some questions and even contact some of the faculty/staff. They may be willing to give your email to a student that will answer your questions better.
Hope this helps.
Spang