I am currently an RPN (with previous university degrees in another field) and am almost finished my BScN. I will be applying to Med school once my BScN is complete, at which point I will have the following letters after my name: BA, MA, BScN... I feel I've got a hearty curriculum vitae and experiences to apply. I have already done all the Med School admissions requirements: Orgo, Physics, Calculus, Stats, Advanced A&P (scored nothing lower than 82%) and I am scheduled to write the MCAT in the spring 2017. I could technically apply now, but completing my BScN is important to me. SO... Personally, I would consider the MD over the NP program because of the wider scope. Also, it's longer and I am of the personality type that is extremely driven, needs consistent stimulation and likes new challenges all the time. I can dedicate the next 7 years to med school + residency because I have nothing else in my life. I am not married, no kids, nothing and no one else to consider except plenty of time that could be filled with more work, studies, self-improvement and professional advancement. So, I figure why not give it a try. Honestly, I would be happy to make the compromise of becoming an NP instead if I had a husband and children... but I've been very unlucky with romantic relationships (ex. abuse) and life is proving that those things are unlikely going to happen for me/ will be very difficult to come by so all my energy gets poured into studies. So, instead I will be a lonely yet extremely over-educated, accomplished spinster and potential-MD.
So, for me I am choosing the MD over NP route is because I have the time, space, resources to dedicate to do it. I was always going to advance my credentials but am choosing this direction because my life can accommodate it. If I wasn't single/childless, I would chose to become an NP. I really don't see one route (MD vs. NP) as "better" than the other, just suitable for different reasons and circumstances.