I think CUBAIT and the Downtown are tougher, but I have to do this:
ASU's Michael Anderson Memorial Challenge (formerly the Revolution):
17/24 were offered or earned ORCS bids (Note: We don't bar people's C and D teams. In fact, we welcome them because we're a local tournament)
6/24 to the NCT. (Also note that we had two Cal in attendance as well as Air Force, all three of whom were expected to make the NCT).
Plus we put real juries full of real people in 19/48 rounds. We also had more than enough judges.All I'm saying is don't rule a tournament out because its field is largely regional. Especially when that region is the west

That said, my money for best tournament is on the Beach Party. That tournament is remarkable in every way.