We just got a Caldera Tahitian, have had it for 2 months now. Love it, quality it there, power is there, looks are there, therapy IS REALLY there. Caldera Tahitian has my vote, but maybe cost more than the 6k you want to spend. I can't speak for the other tubs. I've never even seen them. But this forum will help.
bosox-----------there done.........go Pats...........