Did you discuss your application package with your admissions adviser? Do you know if there are areas that need improvement? The programs serve two different needs - one is aimed at test prep and fitness, the other adds college courses.
Are you seeking a military environment to see if the SA lifestyle is right for? - MMI
Are you seeking college credits that would be transferable in the event you opt-out of a SA and choose to go to a traditional college? - MMI
Are you seeking hyper focus on standardized test prep? - NWP
Are you seeking a 6 month cohort instead of a 12 month program? - NWP
Are you seeking something on the West Coast? - NWP
Are you seeking something in the South East? - MMI
Ultimately, I think you can be successful in either program. There are far more things to consider than these simple observations, but you've come to the right place where graduates of both programs can chime in. Staff like
@Physicsguru also are here to help answer questions.