It's a really, really hard program. Probably harder than dental school to be honest. Every quarter I would have 24 exams in 10 weeks... plus quizzes and working on a Capstone project. That said, I think it helped prepare me for dental school. My first year of dental school all my classmates were stressing because of the courseload -- for me it was no problem at all since I've actually had a crazier experience the year before.
Funnily enough, I also applied to dental school while I was at MWU like you are planning on. I got a few interviews and they let me leave school for a day at a time and do my interviews. I ended up getting in to dental school in January, but the dental school staff wanted me to finish my MA program as a contingency for me starting school in the fall. So I had to finish out the MA program all the way through, which was tough like I mentioned but it's all good.
EDIT: It helped me raise my GPA and also show dental schools that I could "handle" higher level coursework. So yes I think it helped improve my stats. That said, I already had a 24 AA on my DAT, so I think that was a huge factor in helping me get in in which MWU had nothing to do with it.