I think what agr1365 said is about right.. from what I understand, yeah, they pay for your school in return for a 3-4 year commitment, however you don't have much control over where you go or what you do. I know they have like, residencies (like, pathology and other things that would be useful to the military) and stuff, so that would be great, but on the other hand, there's always the possibility that they'll send you to Iraq to be a meat inspector at the slaughterhouses for 3 years... not my idea of a good time!
Of course, this is just what I've heard from my classmates and you know, general hearsay, in order to find out the real deal, you should contact a recruiter to hear what he/she says, and ask for the contact information of someone that received the scholarship and is now graduated and working with the military. I would want to talk to someone that's actually been through it, because from what I understand, sometimes the recruiter might tell you kinda what you want to hear and not exactly shoot you straight.