LOL, I have to tell you I have the same decision to make as you (KCUMB vs. CCOM) but I have the opposite view: being near Chicago is a definite PLUS for me over KC.
I lived in KC for almost two years and Westport and the Plaza is not all its cracked up to be. The city is really limited in its social life (if that's what you mean by "exciting urban area") as compared to Chicago or San Fran. I have not lived in either city (although I have visited Chicago many times since I live so close) but my friends who have say there's no competition. Of course, I would never choose a med school based on the 'fun city life', but I just thought I should warn yout to not be fooled by the 'urban' areas of KC---the city is pretty spread out and don't have much to offer in terms of night life.
For me, I don't plan on having a social life in Downers Grove, if I went to CCOM, I'd go into the city for fun. So if I had to choose between the two schools by its fun quotient, I'd have to go with Chicago. However, I'm mainly leaning toward CCOM for academic reasons (clinical rotations, matching etc)---I can't seem to find KCUMB's match list so it's hard to compare.
Anyway, I don't want to dissuade someone from KCUMB b/c of any preceived deficiencies in the city, but I do want to share my experiences of what living in KC was like.....