Well, if OP goes to a U.S. allo medical school, s/he will most likely get mostly U.S. citizens in his class ... boring! Like my uncle always said, once you have seen one American city, you have pretty much seen them all; sometimes the street names don't even change:
1st Street, 2nd Street, Main Street, MLK, etc. Similar stores ... Home Depot, McD, Blockbuster, Dominos Pizza, Ann Taylor, Radio Shack, etc. The U.S. is not very diverse at all. You have only two major parties: Democrats or Republicans. Heck, Americans speak mostly English some Spanish and the rest is almost in the noise. If OP wants diversity, s/he should go to a Caribbean school because they draw from around the world ... places like Nigeria, Congo, India, China, Russia, France, Lebanon, Iran, Pakistan, Philippines, oh yeah, and the Carribbean (Haiti, Dominican Republic, Honduras, Cayman Islands, etc.), ... now that's what I call diversity!
😉 
I'm kidding, of course, ... I love Americans, but I have no illusions about how "diverse" we are relative to the world when it comes to medical school class makeup (or even demographics of our cities).
OK, I better contribute rather than just joke around. I'll be going to Baylor starting in July and one of the things that actually did impress me about the medical school class *is* the diversity. There were people with all kinds of backgrounds, not only just in terms of education, but races, etc. They did share some things in common: they were helpful, socially comfortable, friendly, energetic, and smart, of course. Although many students were Texas Residents, many went to an out-of-state UG school (at least I spoke to several) or have lived outside of Texas. The Texas Medical Center is hard to beat with dozens of hospitals and institutions, and Houston is a big city that can accommodate pretty much every interest easily except, perhaps, mountain climbing and skiing (we don't have local mountains or get much snow here ... but these are just a quick plane ride away). We have people from all over, and we have lots of sick people to learn how to practice medicine on. The area around Baylor and TMC has many museums, Rice, and lots of interesting people with diverse perspectives.
In terms of the "pros" that OP listed wrt Duke, Baylor is known for its excellent program and if you want to explore research, there are tons of opportunities for that. You can do a year of research in one of the Baylor tracks (the "Research Track"). Pre-clinical is 1.5 years ... about as short as it gets. Rice is not very far, so if you are looking for a campus atmosphere, you can hang out over there (and do research there as well). There is an underserved track and international trips you can go on to serve and explore your future career options. It depends on what the OP wants to do.
I guess I am curious as to what the OP's interests are ... can you tell us a little bit about what you like & don't like (research vs clinical), curriculum preferences, hobbies, etc. Medical schools are not "one size fits all." The answer to your question depends heavily on what you like and are looking for in your education.