Originally Posted by Old Dad
I know a Harvard Professor in STEM who told me, "Don't bother sending you sons to an ivy league school as an under graduate, generally speaking, they're much better off in any number of state or small private colleges as under graduates where professors actually teach the classes. Under graduates just aren't looked upon with much importance at an ivy league school. When they get to the graduate level courses, that's different."
As a physics major at Harvard, I never took a course that did not have lectures by a professor, although some of the lower-level classes also had sections with teaching assistants. It's probably true that the first priority of most professors at elite research universities is research -- that's the primary basis on which they are tenured. But the physics professors were enthusiastic and very knowledgeable about what they taught, and I think they felt that training the next generation of physicists was a serious responsibility. They would not skimp on topics covered out of apathy or the desire to make things easy for students. Many physics majors taught themselves by working individually on problem sets and then discussing them with other classmates, rather than going to professors' office hours. I think this is a reasonable approach.

If you are a well-prepared physics major, coming in with 5's on AP Physics C and AP Calculus, you may be taking graduate courses as early as your junior year, so there is not a bright line separating undergraduate and graduate education.