I'm with @georgehifi . In essence, what they're doing is degeneration the snot out of the output stage to keep it very well behaved. Not a bad option for low impedance, benign speakers. My old ESS sounded great on a Mc. My F5 has a very different character which I prefer, at least with my Focals. I think the Mc got the best sound from the ESS though.
Why do no audio enthusiasts use McIntosh?
With the exception of some of there tube gear, not many really use this stuff(or admit to it anyway), I am mainly referring to there amps. They look pleasant, they look good on paper and have the price of high end gear, but I seldom hear anyone claiming to like or one day dreaming of owning McIntosh. I have never really listened to there stuff, no good word of mouth sort of scares me away from it, the only people who like it are those who sell it, an uncanny coincidence? I don’t know. Sorry it this has been covered many times in the past, I ran a search and could not find anything.