I went to a Seven Sisters college and know a lot of people who went to public and private colleges in the US. I can attest to how things are very different at a private college.

The biggest asset, for me at least, was that private colleges run classes even if only three people sign up. In fact, sometimes this is by design and is called a "seminar class." In contrast, public colleges (especially community colleges) cancel classes with fewer than 20 students as a matter of policy. They also limit enrollment (as do private colleges). Unlike the private colleges, though, State U students sometimes have to wait a year to take a course required for their majors, and many end up spending extra time in college or doing a summer session as a result. Unless things have changed recently, this won't happen at most private colleges (correct me if I'm wrong). Either way, it's nowhere near as common at the private ones.

From the perspective of a learning environment, this sucks.

Alternatively, if you attend a big state university (UMASS, Penn State), you'll have more major options. I took a couple classes at UMASS because they weren't offered at my college. That was nice.

So this is a big advantage at the big universities.