I’m hardly an expert on the topic, but I have several cousins (all engineering) at/or graduated from both UMich and UMD (disclaimer:I’m from MD). Given that they’re the same price, in my opinion UMich is a no-brainer. The prestige difference is real for CS/CompeEng and I believe that was key in one of my cousins going on to an Ivy grad school.
As for your cons:
The cold is a fair point, but Maryland isn’t significantly better on that front; it’s not like you’re going from Florida to Canada or anything. Also, UMD has its own struggles with integrating URMs (http://www.baltimoresun.com/news/maryland/education/bs-md-umd-racial-disparity-20180118-story.html), though it’s still better than UMich just because of the location.
Just something to be considered. Congrats on getting accepted to two great schools.