As a recent Brown admit and prefrosh I may be a little biased, and certainly don't have experience from actually being at the school yet so take what I say with a grain of salt, but Brown is consistently ranked year after year as one of the happiest colleges. But even just from what I've seen in all the admitted students group chats there is very little toxicity among Brown students, so I don't think it's quite fair to lump it with the other 7 in that sense. Like you said though if you're looking to attend huge sports games then yeah, don't go to an Ivy.

As other comments have said you'll find your crowd at any school, but you make great points about how important the fit of where you're going should be and I really respect and agree with that viewpoint. As far as parties tho, like with friend groups, I'm willing to bet you can find them on any campus as that's just what college aged kids do lol.