Also for me MERP was the entry to ICE's FRPG systems, later switching to RM2, then RMSS/RMFRP and later adding HARP. We especially liked the skill system approach in MERP as well as the attack tables and criticals. And we still use Middle Earth as setting, occasionally using the old MERP modules for background information.
I hope that RMU will keep the good parts of MERP and RM and will improve some of the areas where RM had weaknesses. From what I have seen until now I must say that indeed some of the old weaknesses have been removed/mitigated (e.g. wearing armor is now more of an advantage than with the old system), but at the same time there are areas where MERP and RM were strong and there was no reason for changes IMO, but which now have undergone a change to the worse (e.g. rebalancing of weapons, critical tables). So let's see what the next beta brings...