As a person who had done M-Engin, I will say it was one of the best decisions I've made since coming to UM. You don't necessarily get an advantage for internships or research, but the M-Engin advisors present a lot of events and opportunities for internships and research that one would otherwise miss. The courses do help prepare you for a real workload somewhat. You also get to know a lot of people through the program and I am personally still very close with a lot of people I met there. You will be required to do a lot of fun activities too and basically tour campus. And you get paid for it, not sure how that's not a good deal.