This is just from my personal experiences in talking to people from the various schools so take it for what its worth.
Loyola students seem to be the happiest. The school makes a point of giving students time to have a life outside of med school. New facilities and a very student friendly atmosphere. Few complaints.
UofC students are also generally happy however it does seem like they spend many hours in lecture. Nonetheless they seem to take it all in stride b/c the administration seems to be very supportive of them. The teaching is excellent and profs seem to take a vested interest in their students. Located in Hyde Park which is generally decent but is surrounded by urban ghetto.
Northwestern students also seem generally happy about their school. Few complaints from them. Med school is located in a beautiful location off the lake (north side). Expensive however.
UIC, well the good news had to end at some point. About the worst thing I've heard about UIC is that its just a plain POS. About the best is that yeah, it's a POS but clinical years are excellent and everyone ends up matching well in the end. Highly competitive student body and a very unsupportive administration. UIC is only for self-starters it seems. Located on the west side.
Rush, similar to Loyola in some ways however it does not have religious affiliations. Supportive administration and student's seem generally content. Located on the West Side very close to UIC in the Chicago Medical District.
Finch, I've lived in the norhtern burbs of Chicago all my life and never heard of Finch until two years ago. Haven't met any students from there so I really can't say much about it.
Located in Waukegan, a suburb about a 40min drive from chicago with no traffic.
Again this is only what people have told me in my own investigations. Good Luck!