RM2 in 90 - 92
RMSS in mid-late 90's
AD&D 3/3.5 in 2001-2004
RMC - Starting new campaign (at least the plan)
The players who have played in my campaigns all liked RM better than AD&D. They are not passionate about which RM (though they have never experienced RMFRP, nor probably never will).
I have roleplayed since 1980 in AD&D (skipped all 2ed), Palladium, Gurps (name the flavor), GammaWorld, Boothill, Champions, RM, Deadlands, Traveller, Masquerade, Chthulu, Paranoia, etc.
Of all the worlds and all the systems, my love still falls to Shadow World and Rolemaster, followed by Forgotten Realms and Paranoia. (Much fond memories with Paranoia. Never a campaign, because you could never live that long. Just a lot of stupid fun, smart comments and creative deaths!)
All hale Shadow World/Rolemaster!
Brim