Try to see if the departments or admissions teams can connect you with other international students from the US, even those at the graduate level. Their campus experiences might be informative and get to the heart of some of your concerns. You mentioned both location size and a large university feeling. Well, Durham and Glasgow can both give you a large university feel, both have large undergraduate student bodies. Their enrollment numbers are much higher than most of the top private US universities. However, you're right, Durham won't have that same city feel as Glasgow. But is that a bad thing? I don't have an answer for you in that regard. I have heard of Glasgow being compared to both Boston and L.A. I think Boston has a great feeling, but I'm not a fan of L.A. Personally, I would choose the program with the better academic reputation. From a cursory glance, that seems to be Durham. Have you considered visiting the universities and talking with both the students and professors in the departments before making your final decision? If you can, give it a go! If not, reach out to them online and see what kind of feedback you get.