Until I'm lucky enough to get in, I'm not going to give that a concise answer!
But I won't leave you hanging either...
Short answer: Michigan was my top choice when this process started, and it would take a pretty incredible school to lure me somewhere else.
Longer answer:
I had a pretty incredible time in Iowa! If I'm lucky enough to get in. I will definitely take a long, hard look at both schools.
Let's put it this way: if UofM weren't in the running, Iowa would absolutely be my clear-cut #1 choice at this point, no where else has been close. Just like in the old days of Big Ten football, I'm looking at the big two, little eight. (Yes I know that was UofM and OSU in football, and now it would be big 2 little 9, but give me a little poetic license...!)
Here's what I liked about Iowa:
The CELLS (though I've heard that no one actually calls them that.) It isn't that I want my med school set up like Hogwarts,
I really like the idea of the cross-year, M1-M4 social and academic interaction that it would foster.
The people are great: friendly in a midwestern, unassuming way, but also very capable. I thought the admissions office did a great job, and I really liked the students and faculty that I met.
The facilities are great. I have a hard time believing that anyone has newer/better facilities than those I saw at Iowa.
Iowa City. What a great college town. I'd heard a lot of good things before I went there, and they absolutely were inadequate in describing the atmosphere. Incidentally, my cousin played football at Iowa, so after my interview I went over to the football office to track down some old team photos. I ended up talking to one of their coaches for a while. After learning that it was my first trip to Iowa City, he asked me not to let the secret out on what a great place it is so that it won't get too popular and change too much!
Good mix of traditional and nontraditional students.
I like the midwest and midwestern weather, so those fall in the plus column for me too.
Bottom line: I felt that it was a place I could be very happy and successful. (One of my interviewers said as much as well.)
Potential drawbacks:
Cost. If I'm lucky enough to be choosing between the two, unless Iowa decides to show me more financial aid love (entirely possible) I'd be looking at in-state vs. out-of-state tuition.
Reputation/expectation. An example that was given (twice) of Iowa students doing great things was a girl who is at Michigan for residency. I got the impression that they view themselves as pretty darn good, but not quite even with Michigan.
Parting thoughts:
I know that some of the Iowa admissions folks read SDN. If you made it this far & know who I am: Show me some love!!!
I'd love to be a hawk!