I don't think either school will give you an edge over the other in terms of securing a residency. Medical school is what you make of it. You should attend the school you will be most happiest and comfortable at. I highly recommend AZCOM but I will try and give you strengths and weaknesses of the school to offer a balanced opinion.
Strengths
(1) Campus, facilities and weather (300 days of sunshine and 70 degree weather in February can't be bad)
(2) Friendly, bright and laid back class - I can genuinely say I love my class. It's rare that you will interact with so many bright yet laid back people in one setting. Upper classmen are supportive as well and will go out of their way to help you.
(3) Board relevant curriculum- From day one, the curriculum is designed to help you excell on the boards. Exam questions are written like board questions. Material is taught in a concise pattern. Textbooks are often board books. Extensive COMLEX and USMLE preparation is integrated into the second year curriculum more than I have heard at any other school.
(4) Location: Arrowhead is a very wealthy suburb. Median home prices approach 500K in the area. Any restaurant you can think of is within 15 minutes from school on Bell Rd. It has everything you need. If you want to go out, there is great night life in Phoenix, Scottsdale and Tempe. Las Vegas, Los Angelas and San Diego are 4-5 hours away by car. Several luxury apartments are accross from school. Campus housing is pretty nice. Homes in the area are affordable if willing to drive 15-30 minutes away.
(5) Matchlists - the results speak for themselves. Check out our matchlists.
http://mwunet.midwestern.edu/academic/AZCOM/azcomDean.htm
Weaknesses
(1) Class heavy schedule - We have an 8-4 schedule for the most part. Some classes are extraneous such as the workshops
(2) Exam schedule - can be brutal with exams every other week. During second year, you have exams twice a week.
(3) Tuition - tuition is increasing and is rather high
(4) Weather: It's pretty hot in the summer as you obviously know.
(5) Location: Although Scottsdale, Tempe and Phoenix have fun things to do, it is pretty far from campus (30-40 minute drive) so most people don't go out that often. We tend to stick to house parties and bars close to campus
In the end, I would do it over again and choose AZCOM. It's an excellent school and I don't regret my decision to attend it. I was just trying to be fair by offerring 5 weaknesses. Keep in mind that every medical school has its flaws,it's just that not everyone is willing to admit those flaws. DMU has its own strengths and weaknesses too. I have heard great things about DMU but I'm more comfortable attending a school in a large metropolitan city.