willvr:
just because 3.5, or DnD in general, has lots of crunch to it, it means that 'real' role-players shouldn't play
I often mention (both because it's funny and very true) that my home group's most RP intensive sessions happened in D&D 4e. That's not because D&D 4e is not crunchy (it was, by far, the most "miniatures wargame" version of D&D). It was because combats in 4e took so long and were just generally so painful to do that we did everything we could to avoid them.
Anyway, on the general topic, a metaphor might help. Let's say you have a few sheets of paper and a pack of crayons and you want to make a picture.
The first sheet of paper is completely blank. This is your freeform game. You can color absolutely anything you want within the loose confines of the "page". This offers you a maximum degree of freedom, and absolutely no guidance. Some people are going to love the freedom, and others are just going to stare at the page in indecision.
The second sheet of paper has a "connect the dots" style series of points on it. You have some degree of guidance and some degree of freedom (depending on how many dots, whether they are numbered, etc.). This is a representation of the various rules-lite systems. The exact mix of guidance vs. freedom will vary by game, and different people will like different ones. Still, some people aren't going to like this system because it's too restrictive and others aren't going to like it because it doesn't provide quite enough guidance to make a good picture for them.
The third sheet of paper has a normal coloring book line drawing on it that you can fill in. You're free to color the picture however you want and maybe draw some stuff in the edges of background to add a little flare to it, but the overall picture is constrained by the line drawing. This is a rules crunchy system. Some people are going to absolutely hate it because they can't make the drawing they want with the lines that are there while others are going to love that they already have a framework for their picture.
In the end, it's all down to the things individual people find enjoyable. For instance, I sometimes appreciate the submission type of fun (not that kind, you perv). That means I enjoy a game where I can turn my brain off a little and just play the game. D&D-type combat tends to be like that. I know my abilities, I know my foes, and I play the game to make them dead. I don't get any of that type of fun out of a FATE game. There's no "turn your brain off" in FATE since everything requires creativity and narration.
On the other hand, I sometimes get frustrated with the restrictions in particular games (the expression type of fun, mostly). I can't build a character that does x in system y because it just doesn't work that way or the system, for whatever reason, values x very highly. That's when I do find games like FATE appealing for the freedom they offer.
Further reading on the types of fun:
http://www.gnomestew.com/gener...-eight-types-of-fun/