USNews ranks FSU above ISU. And being in the AAU means you have had qualities that allow you in the club, rather like the local country club in that way. It, however, does not mean your school is academically superior. Ku is in the AAU - West Point is not. Notre Dame is not. Dartmouth is not. Tulane is not.
Rather than searching for which good schools aren't in AAU, just go through the list of schools that are. I'd rather my school be in the company of those schools than the rest.
I actually selected ISU based on a US News ranking of the engineering school. But that was before I knew any better.