It's interesting to me to see all these posts commenting on the relative merits of the storylines. I don't think the overwhelming majority of people think of LEGO lines as even having any stories beyond what kids imagine for them. Are we talking solely about the bits and pieces of story disseminated through the sets' catalog listings and the PM website and so on, or are there actually extensive, detailed narratives publicly available out there of which I'm totally unaware?

(Actually, come to think of it, I do know there were video games for RR; are those part of what we're talking about?)
RR was winding down right about the time
SW brought me out of my dark ages, and hence I never got any; the last ones available were going away just as I was beginning to buy other LEGO sets than just
Star Wars. I so often wish I could have come out of my dark ages at least just a year or two earlier, so I'd not only have gotten more
Star Wars sets but also a number of others from around the late '90s / early '00s, and have a few more LEGO themes represented in my collection by at least one or two sets.
Getting back to the question, I actually sort of conceptualized PM as being a continuation of RR (are the narratives different enough to preclude this?), and the major differences appear to me to be PM has a greater focus on the conflict with the Rock Monsters (RR has some conflict against the larger monster as well, it seems, but it's not as central to that iteration of the idea), and of course the different color scheme. On this I'm torn - the RR color scheme seems more naturally suited to the theme, but I love, love, love green, especially a really bright green, so the prevalence of all those lime bricks in PM speaks to me. Part of me also thinks I should vote for PM simply because it's the incarnation to which I do have access, while part of me thinks I should vote for RR for precisely the same reason...