I’ve been here about three weeks, so take what I say with a grain of salt, but:
It’s a very social school. There are a lot of parties, which as a non-partier, I find kind of annoying, but if that’s your thing you’ll probably like it. There are other options, though; reslife (I think) sponsors a Free Food Friday event, where they provide pizza and board games. It’s nice. And, obviously, people just hang out in their dorm rooms or go out to the movies or things like that.
People are nice. Truth be told, I’ve found it very hard to make friends, but there are personal reasons behind that. In general, I don’t think people have trouble. It isn’t cliquey in the stereotypical, “high school” sense.
The sports teams aren’t really prominent, I guess. I’ve heard of postgame parties, but those aren’t a major thing. The first football game was yesterday, and I know some people went, but a lot didn’t. I guess I’d say that sports are there if you want them, but you won’t feel isolated if you’re not into them.
(I assume you mean Brown, not Williams :P) How hard is it to succeed? That’s a loaded question, and one that I’m probably not eligible to answer in my first semester. But I’ll take a stab at it anyway. Compared to other schools, I think it’s easier to succeed. Obviously, you still have to work hard, and you can’t slack off. But the fact that you can take any course S/NC makes a huge difference. And you literally can’t fail a class. The lowest you can get on your transcript is a C. If you get below that, it just doesn’t show up in your records. At all. You can still fall into poor academic standing if you don’t pass enough classes, though. But there isn’t the grade deflation or hyper- competitive atmosphere that you find in other schools.
Class size? Depends. Intro courses are large lectures that typically have smaller-group labs or sections. I’ve heard that STEM classes tend to be bigger, though I can’t verify that. I’m in a large course, a medium-sized English one (around 30 people) and two small ones (10 people or under).
General vibe? I don’t know. I think in general, Brown is a school that its students love. Most of the people I run into seem to be thriving. You’ll hear often that we’re the happiest Ivy, and that seems to be something people really embrace and live by. That being said, I’ve found it kind of hard to adjust. I’ve continuously felt that I would be much happier in a different environment. This might not be something to take seriously – I’m three weeks in; it’s probably normal to feel this way. But I mean, ask me how I feel during the second semester.
Hope that helped. Good luck with your application.