I think the biggest difference between UChicago and a state school is that the state schools will have a cross-section of their state, while UChicago has a nationwide cross-section of the upper class.
So you might have someone in your house or in a class who has strong opinions on the relative merits of a bunch of NYC restaurants most people couldn’t afford, someone else who knows all the gossip on DC prep schools, one or two people who spent their high school years hanging out in hip parts of SF, one or two people who took gap years and traveled the world, etc. Lots of lawyers’ and dentists’ kids, or people with a parent in management consulting, or kids of academics. On the flip side, you might get someone who worked 30+ hours a week to provide for their family in high school. It’s rarer to see kids whose parents are medical assistants or plumbers and make $60K a year.
The people at UChicago, like most groups of people, have an incredibly varied set of interests. There’s a case to be made that, because most students hail from the upper crust, they have more time, resources, and access to information, leading to a more eclectic set of hobbies and intellectual interests.
The community is fairly progressive in some ways - particularly socially. Anyone who decides to shame someone for their sexual orientation, or say racist stuff, or make creepy advances on a classmate, is going to have a very rough time.
We also have some serious blind spots. People who plan house trips on the assumption everyone can spend $20 on Uber, or are astonished when not everyone knows some niche reference, or talk about the South Side the same way they’d talk about Aleppo or Eastern Ukraine. I know of one person, a real piece of work, who made fun of a housemate for not knowing a (very expensive) brand of clothing.
Most of the time, this stuff doesn’t come up, and you’re just dealing with a bunch of friendly young adults. It is possible to be rich and perfectly nice, or be a classist idiot and also have excellent taste in movies and a strong grasp of linguistics. And most people are nerdy about something. But you can feel the difference between UChicago and a state school or UChicago and a high school in a working-class area - for better or for worse.
More generally, I have found people here to be supportive and welcoming. A big change for the better, relative to high school, was a sharp drop-off in toxic competition. My high school saw a lot of people who compared grades, worried others would get into a college and take “their” spot, argued over who was smartest, etc. We don’t do that here. Your classmates and housemates want you to do well, and want to do well themselves. These goals aren’t mutually exclusive, and nobody sees them as such.
It’s a weird environment, but I’m happy with it.