tournament last season. Also since most P5 teams spend the bulk of the non-conference playing Q3/Q4 games, there is not a large body of evidence establishing superiority one way or the other.
I think Big 12 and SEC both finished the NCAA tournament last season at .500 (SEC 8-8, Big 12 7-7), but SEC got one team in the final 4 and two teams in the elite eight, and Big 12 got 0 for both of those.