Mayo in Rochester is a great place to do an acting internship fourth year. Not only do you have to apply early (makes you get your ERAS stuff together faster) but it's excellent experience in one of the best teaching institutions in this country. Mayo is the closest thing to an apprentice-type rotation that is out there.
A letter of recommendation from any clinician at Mayo is a huge advantage when it comes to application for residency anywhere. Besides, if you are good enough, you can be awarded a scholarship to cover the cost of your housing and transportation there. I had the scholarship and ended up having enough money to come home and go to some of my away interviews.
The key is that you have to apply early and do your AI early in the year. Any rotation at Mayo is a career-changing event. They teach you many great things that will make you a better resident no matter what medical school you are attending. You also get practically individual attention from the attendings as there are so few medical students, you are treated like a junior resident.
While I wouldn't go there for Trauma Surgery (not much trauma in Rochester, MN), just about everything else is awesome. My Mayo rotation/scholarship coupled with my AOA opened many doors for me. Almost every PD at every place that I interviewed commented on my letter from my Mayo preceptor (a world-renowned endocrine surgeon).
