My friend’s having difficulty in choosing between the two, so it would be very helpful if you could share your perspective 
Please read:
What is it like to attend McGill University as an American undergrad?
https://www.quora.com/What-is-it-like-to-attend-McGill-University-as-an-American-undergrad
I like the quora link from @TomSrOfBoston.
Rochester is kinder and gentler if you need that, and there is nothing wrong if (s)he does. That’s really the main difference. The better place is the one where your friend would more likely be successful. The decision is not about the school it’s about your friend.