I really liked MERP(the first "professional" game I've ever played/GMed), love HARP and have mixed feelings about RM, although the only edition I ran was RMFRP. I mean it's a really great game, but it's kind of like Dream Theater music in two ways, one it's very hard to get into it at first so it's understandable a number of people don't like it and two it has some unnecesary complications, like the multiple maneuver charts or the whole "one table per weapon"(I know they are optional). Once you can get past it and create the characters without dying in the process, it's really great. But you can't ask everyone to be willing to make that journey. And it's certainly a challenge for those who jump on it without having played MERP or HARP.
It's easier to see why MERP is in there. It's not just the Tolkien thing(the One Ring is a lot lower on the list), but it's a very straightforward game. Character creation was fast, even if the price for it was a little cookie cutter characters but newbies don't care about flexibility, in fact the less options the better. The mechanics have all been improved with HARP, back then they were easy enough to run even for a 13 year old like myself back then.
Too bad seeing HARP that low though... I hope the new Bestiary and Cyradon come soon, otherwise it will be hard for new players to get into it.