In my experience, there is a large gap between the smaller, liberal arts "teaching" college and the large, research institution. I did my Bachelor's at the former and had great teachers and small classes (no classes with more than 30 students in 4 years). I did my Master's at a Research I university and there the undergrads are put into huge classes taught by professors that couldn't care less about them and grad students who are overworked and underpaid. Of course, at the graduate level the tables turn in the student's favor again: the Research I university offers small classes taught by some of the foremost experts in the world.