Top U.S. business schools are basically M7, Sweet-16 (M7+9 other top schools), for a total of 16 top schools. These are considered elite MBA programs.
UT Austin is often ranked 17th in US, but there is a huge gap between Sweet-16 and the rest of MBA programs in terms of reputation.
A few top European schools are of Sweet-16 quality, but hardly any should make into M7 level.
Of the M7, Harvard, Stanford and Wharton are undisputed leaders. There is a noted gap between these 3 with the rest 4 (MIT, Northwestern, UChicago, Columbia).
The 9 other schools in Sweet-16 are pretty compatible, with UCB, Dartmouth, Duke having a slight edge.