I'd have to go with KCUMB.
I just got done making this same decision. I choose KCUMB. When it came down to it I set aside location, which was the main thing holding me back from choosing KCUMB over Nova.
What I liked about Nova was:
1) Location
2) Campus (gym, library were great, but I never got to see any of the medical schools facilities)
3) Tuition is not too bad compared to other DO schools
What I liked about KCUMB:
1) The medical school facilities were great, the patient simulator, new auditorium, Library, anatomy lab, OMM lab etc.
2) 3rd and 4th year rotations (1 elective 3rd year and all electives 4th)
3) High percentage of graduates that specialize
4) Systems based curriculum
5) The people, I felt much more welcomed by the admissions staff, students, and interviewers at KCUMB than at Nova.
6) Kansas City actually surprised me, maybe my expectations were low, but the city itself seemed to be plenty modern and going through major revitalization. Only thing is the cold, which my SO is not a fan of.
I have not received decisions from about 20 MD schools so I will be in Kansas City next year unless I get accepted to an MD school I find to be a better fit.