The only thing I know about Copeley/Faulkner is that they are really far away from central grounds, and the two transfers I know who lived there complained that the distance made it hard to get involved on grounds. Hopefully someone who lives there or language houses can comment.
The IRC does have single rooms. It’s about evenly split between international and domestic students, so the cultural and linguistic diversity is incredible. And I’m not international at all - never been outside of the country - and I enjoyed the environment. Like all RCs, it has a lot of events, particularly in athletics. It also probably has the most free food of any dorm on grounds. One of my favorite events was this dinner series where a professor hosts a small round-table dinner to discuss their recent projects.
Brown is a little more offbeat; the people who live here tend away from the UVA mainstream or stereotype. My perception is that Brown has a little bit more of a close-knit community, because it has a central lounge that people congregate in, whereas the IRC is somewhat more spread out and diffused socially. But I will also say that I’m more active in Brown than I was in the IRC, so I’m sure the IRC has a strong community if you choose to get involved. Brown is all singles, but it’s kind of hard to describe - basically you have to walk through your roommate’s single to leave or access the bathroom, so you have your own room, but sort of also have a roommate.
Both colleges have lots of events going on, and both have good locations, though Brown’s is a bit better. Also, if you apply to the IRC you’re very likely to get in, whereas Brown has more selective admissions.