So, We don’t know much about Univ. of Richmon (except it is a great school). Son has to debate between Foundation at UGA and Oldham Scholar at Richmond. I would love some input as he is needing to make decisions…
If you can visit the two schools, perhaps for accepted students days, it would likely help him to decide. There is a huge difference in the size of the schools so would he prefer a LAC or a large state school? I’d get some college guide books (ex. Fiske, Princeton Review, Insiders Guide) and read up on the schools.
Well, congrats to your son for two big scholarships!
I agree that the primary difference between these two is going to be size and feel - University of Richmond is a small liberal arts college focused on undergraduate education; UGA is a huge research university with a mix of different types of students. The sizes of his classes will be markedly different, even on the junior and senior level. UGA also has a much wider variety of majors and more pre-professional ones, like advertising and actuarial science; University of Richmond has a more liberal arts bent (although they do have a well-reputed business program).
Congratulations!
I’d go with URichmond myself, because I like the personal attention/mentorship and interactive classes such colleges offer undergraduate students, but if your son is into football I bet UGA would win out. 
I do not know U of R at all, but can give general info about UGA. It is in the perfectly suited college town of Athens, and the music scene and social activities would be plentiful. Not sure where you live, but Athens is about one hour from Atlanta if you need a major airport to fly in and out of.
What is your son’s intended college major? And is he ready to live on a college campus that is its own city? My D freaked at seeing the large city buses rolling through campus to shuttle students around. But for others it is a good thing.
If your son has not visited already visited UGA, I strongly encourage you to make that happen before you make your decision.