I too have noticed a sonic difference between v6 and v7 MEA-2 compared A/B.
V7 was "cleaner", V6 had more "mojo", if that's the right way to describe Maselec kit .... or you could say it was a bit "gritty" by comparison.
Warning,shameless plug coming:
My MLA3 sounded great to me though and although I questioned the need for it and almost sold it 2 years ago, I kept it in the end. Unfortunately the time has come to raise some cash and since it doesn't get used a lot here I decided to sell it after all. Anyone interested please email me. I'm near London, Uk.