Pros: Because small colleges usually have few or even no graduate programs, the focus is squarely on the undergraduates. Teachers are more student-oriented than research-oriented, and classes are taught by professors, not TAs. Class sizes will be smaller, even in the basic core courses, so if you dread huge lecture halls and like discussion-based classes, a smaller college might be for you. It’s also more likely that the professors will be accessible and that they will actually know you, and many of the small colleges that I’ve visited make sure that every student has an adviser.
Cons: Small schools won’t have as many departments or course offerings as a large university, and their facilities are likely to be less impressive or on the scale of a large university. A large university is more likely to have any major that interests you, though you may have to enter directly into a certain college within the university as a freshman. Large universities are mostly research-oriented and therefore can have state-of-the-art research going on. Small schools may have school spirit, but they won’t have 50,000 fans cheering on the football team; they may not even have a football team.