I liked them all. They are all RM.
RM1 basically morphed into RM2 with a nice box set that but everything into one box and three books.
RMSS was born from RM2. Play them: they are all the same game with different options for handling everything from Stat generation and development points and power points and stat mods and skill cost...yet, the game remains the same.
I would never have spent as much time and money and storage space in my home on this system and hobby if I did not like Rolemaster, period.
The part I don't like is that while once materials were available, very GOOD materials, now the game is dried up. We can talk RMC or RMFRP till we are blue in the face, fact is there is no walking into the hobby store and dropping $20 to $100 bucks on RM books with excellent writing and adventure hooks and setting and etc. Yes, there is a trickle of stuff (albeit mostly usless for those of us who set aside RM2 and went full bore RMSS and retain most of that old RM2 stuff anyway), but even that stuff is inconsistant and mostly keyed toward providing old RM2 players with something they should have bought a long time ago (just how I feel; I STILL have 6 copies of arms law, down from a high of 12, all from the now old RM2 boxed sets, AND two RMSS arms laws, AND Ten Million Ways to Die...you get the picture, I've been there done that).
I'm more concerned with RM simply being here tomorrow with a supported system sitting on game store shelves for immediate purchase so some other 11 year old kid can find it and enjoy it.