Quoted from CaptainNeo:I don't think it's a joke, I think 83% of the time it's fact. They buy them based on looks, so i'm sure gameplay is a low priority.
Themes prove that, with how many people preorder before actually trying something... and that's fine. I totally get why some people go that way, and it makes sense. To me, I can't love a game unless I love it's gameplay, which is why I have stuff that I think has the stupidest themes (VND, I'm lookin' at you), and the stuff with the themes I would like the most (IJ I'm lookin' at you) I can't bring myself to own generally. I sort of have a joke that if I love the theme, I won't own the machine, but if I dislike it chances are good...
I also own a few machines not because they have good rulesets, but just because there is something silly fun to do on it. Like CBW, that is a theme I don't really like with rules that are miserable, but I could just try shooting that stupid cue ball to the top of the playfield all day and be happy.
Having said that, for me, the best rules have to do with my style of play, which means not deep. I'll tell you that TSPP / LOTR / etc are all deeper rules and are 'better' if you want that sort of thing. I like challenging, one-more-time gameplay, so...
Tier 1 (these games are just about perfect to me, in order...):
IM, JP*, VND, MET, 4 Square (the EM, yeah, seriously)
Tier 2 (these games are a step down, but if set up nasty are awesome...):
WCS, JD, RFM