There are schools better in individual subjects - Rutgers in philosophy, for example - but overall Brown and Penn have a breadth and depth in the humanities rivaled by VERY few colleges. Dartmouth is not quite as well-rounded as either, but it is a solid option for the humanities as well.
Brown is excellent in those areas, but Penn is as well. Penn is stronger in anthropology than Brown and has some amazing resources like its world-renowned anthropology/archaeology museum. (The Haffenreffer and the ancient galleries of the RISD museum are nice, but they’re not on the same level.) Penn is at least as strong in Classics as well, and it’s arguably stronger in related fields like Egyptology and Mesopotamian studies, though I highly doubt any undergraduate would notice a difference academically between the two schools.
I agree that the two are more or less interchangeable for English, history, art history, etc.