I've played and owned MMs from all eras, can't really say that any era stood out as best. The pre-EBs were differently voiced in my estimation, as I started off on a 1990 one I just found the Pre EB different, not better though others opinions vary. One of the best I played was a 30th anniversary, lovely smooth sound and impeccable build quality. My current Starry Night PDN 2016 comes pretty close though and I prefer the ebony board.
So in brief, my opinion, as voiced by some above, is that there isn't a golden era but there are great, good and mediocre examples from each decade.