I tried all 3 version's on an,d there was a marked difference in comfort for each, the Mk 7 was really snug, compared to the Mk 1, and you could feel the price difference, but i couldn't afford the price tag. The Mk 6 also felt so much nicer on, compared to the Mk 1 so plumped for that.
If you do some searching you can find the Mag 6 pretty cheap against it's retail price, but i found they only had obscure sizes left.