<p>Choose primarily based on fit as cliched as it sounds. Chicago is an absolutely phenomenal school, however, its policy of grade deflation could be detrimental to your chances for acceptance to med school. Duke and Penn are very similar schools in terms of academics and social life. Duke has better weather (of course this is subjective) and in my opinion, a more beautiful campus. Penn is in a rather sketchy neighborhood in Philly but then again Durham is no NY, although drastic improvements have been made to the city. Duke is also 8 miles from Chapel Hill which is home to a wide array of bars, pubs and restaurants. Duke has a greater sense of community and school spirit because of Duke basketball, and from my experience, pre med students always seem to collaborate on projects rather than engage in cut throat competition.
All great schools, visit if at all possible and then make a decision.</p>