We often hear about the advantages and disadvantages of large versus small schools. The fact is that there is tremendous overlap between the two. At a very large university, a student can be in his her own small world, depending on the choice of major or individual college within that university.
Certainly, there are many small- to medium-sized colleges. Many students find these appealing because it's easy to get to know fellow students, including upperclassmen, as well as professors. That adds a tremendous amount to the feeling of community and belonging. Students get close friends and move their way up the classes with these students.
At the same time, small schools do have their limitations. Sometimes, there aren't enough course offerings within a particular department, or the student's choice of departments may not even be at a small school. Some students get tired of the "same old people," and like the feel of a larger school where they can continually meet new friends. Outside of the classroom, there are generally more sports, intramurals and extracurriculars in larger schools.
Then there's the whole notion of the college versus the university. Typically, though not always, a college is focused on the undergraduate, while a university may include graduate schools. Sometimes this is an advantage for the undergrad who may place out of courses and want to take grad-level courses while he or she is still an undergraduate.