These are places where you can probably engage in a wider variety of activities than you might be able to do at a larger university. Chances are that it will be easier to develop closer relationships with the faculty and exploit opportunities like student research. The down side is that these can become claustrophobic after awhile. Large universities, by definition, have far more options both academically and extra-curricularly. They will place more pressure on the individual student to develop a social life and make your way on your own.
Some people say large universities offer opportunities for a more diverse group of friends.
But this can get tricky. In practice, many people at a large university, take up with a small group of friends early in their first year and stay with them throughout their college career. The choice basically boils down to your own personal needs and learning style. If you value being part of a supportive community and relish close contact with faculty members, then a small liberal arts college is more likely to suit your needs. If you value being on your own and find that you thrive in an environment with stimulation from diverse directions, then the large university may be more to your liking.