My guess is that out of the top 20 in the states, things fall off really quickly, since there is a lot of cherry picking before that. You really only have a few state flagship and Ivies (or near Ivies like Stanford) that are really good. As a counter, my experience at EPFL (one of the two Ecole's in Switzerland), I found it a bit behind where I went University of Washington (flagship research, public) in rigor and its grading curb. But UW CSE is top 5, so I wasn't really comparing apples to apples.