I am one of those who believe in the Mark VI mystique. My personal opinion is that it is the best saxophone ever made. I agree that other brands are fine instruments, but the Mark VI's combination of solid construction, key layout innovation and flexible tone quality has never been surpassed.
Certainly not by Selmer, I have play tested every model Selmer has made since, starting with the Mark VII, and none of them are as good as a well set up Mark VI. They are heavier, the keys are not as well laid out, and they don't sound as good.
Actually, for alto I prefer the SBA, or Super Balanced, horns to the Mark VI. Lighter and a better sound. Many tenor players feel this way too, though I am not among those. My Mark VI tenor is wonderful.
For many years, most "modern" horns have been copies of the SA 80, in various ways. That's beginning to change a bit, but the general format remains the same - offset right hand, left pinky table with floating Bb key touch attached to the C#, high F#. The only real innovation in saxophone mechanism I have seen is the new Eastman "DS" mechanism, borrowed from Haynes flutes, that is noticeably quieter and more nimble.
All this is just my opinion of course... but I know a fair number of saxophonists and the great majority of them own and play Mark VIs.
But the myth of mark vi is totally fake
Definitively the mark vi isn't not the best saxophone ever,
1) mark vi soprano/sopranino isn't very good reputation and i understand definitively why
2) mark vi low A are not the best, couesnon win largely
Couesnon monopole conservatoire and mark vi was developped with Marcel Mule too,
During this period, Couesnon monopole conservatoire was superior in quality and price of mark vi, but couesnon wasn't very good in marketing, selmer yes
For strange reason, the mark vi cost 10x couesnon monopole, and the myth is around mark vi and not couesnon monopole conservatoire.
I loan my couesnon monopole low A high G at saxophonist who have mark vi Low A (the mark vi was in overhauled)
Definitively, it suggests one tarde my couesnon low A high G and this mark 6 low, i say definitively no
He says me your couesnon low A alto high G is the best alto that i played before.
For my experience, don't underrated couesnon, don't overrated mark vi and Selmer,
They're not best sax on ever made, it depends largely on your experience, your story, the best horn is the horn that your choice to buy and play.
That's my opinion, and i know the Lucky to have my collection.
And for me the best horn that i played is my Adolphe sax c soprano 10171, and my conn f mezzo soprano and buescher tipped bell, because only depending on my story