Ahhh, a very good question.

Vintage Krug IMHO is a bit like Salon - playing is a different ballpark to the rest.

Drinking now? the 1985s are looking really fantastic right now; the 1990 is likely the one which will be head and shoulders above the rest in 10 years time though. The 1996 (not yet released) could be one of the greatest champagnes ever made - we'll see; it will be phenomenally backwards for a very long time.