From what I can tell, the MD or DO aspect (or non at all) of SMP programs probably isn't a huge deal in Texas. The only one we have here is at a DO school and it comes highly recommended by all of the medical schools here, though this could be by virtue of it being in state more than anything related to DO etc. If MC isn't even affiliated with a medical program DO or otherwise, I don't feel that it matters much in regards to Midwestern being one, though like you said, its hard t tell about the relative value of that from this vantage point.
I guess the biggest overall problem for me is the atmosphere. I know it shouldn't matter but living in Glendale seems infinitely better than living in small town Clinton. At the end of the day it will boil down to what is the best program for helping me to get where I need to be. If it really doesn't matter (after all, they serve the same purpose) id rather be somewhere I would like to live. Admittedly I don't have any direct experience with either place so this could change when I go visit.
Also worth noting, the MA of Midwestern vs. The MS of MC is mildly irritating. Again, I'm not sure if it matters because they both serve the purpose of being preparatory but it is something.