I haven't read the Twilight books. I probably never will, at this rate. After all the negative press from people whose tastes I trust, the well has been poisoned so thoroughly that not even a Superfund cleanup would help.
What I have heard about the books set off alarm bells all up and down my critical faculties, so you can imagine my surprise when I read a critique of the books from a story-construction POV and found that other people were already roasting Twilight for things I suspected it was guilty of. One of the biggest was the relationship between the two principal characters, which sounded creepy / stalkerish in a way that didn't serve the story in the slightest.
Then I read this gem, on a board dedicated to giving the Twilight books a thorough dressing-down:
... just because something is fantasy does not mean it is unrealistic. The object of writers is to make you believe the story they are telling ... A good fantasy can utilize the idea of soulmates (like Richard and Kahlan in Terry Goodkind's Sword of Truth series) while still taking time to develop the relationship and the characters in a believable fashion. Attraction =/= everlasting love. Everlasting love happens when you get two people who understand, respect, and enjoy the other in terms of personality and character. Edward's hotness and Bella's delicious blood do not a soulmate make. And justifying the pitiful relationship development with "it's fantasy" is only a crude cop-out reserved for those with no understanding of good storytelling. [*]
That sums it so succinctly there's very little I can add on my own, but here goes.
The other day a friend of mine who'd read both Summerworld and The Four-Day Weekend mentioned that she liked Summerworld, but adored 4DW. The former was fantasy, albeit well-tooled; the latter was her life writ small, and there was so much in it that she recognized and was able to plug right into. I admitted that had been exactly what I was aiming for, but with both books: in Summerworld there's a lot that goes on which is outlandish and fantastic, but it's all rooted in real human need and behavior. It doesn't come out of (or go into) a vacuum. I don't mind a story that features people who suck each other's blood and turn into monsters. I do mind a story that would pretend the logical emotional consequences of such things can be simply hand-waved aside or turned into emotional pornography — which, from the sound of it, is what Twilight's really, really good at.
People are not heroes because the author tells us so, but because the heroes go out and demonstrate their heroism. Guin is a hero: he sticks his neck out first when there's trouble; he takes responsibility for his actions when they fail and credits those who helped him when they succeed; he keeps his sense of humor about him; he never says die. He makes Edward look like the flabby, sullen wimp he is. Now: which one of these two book franchises is currently selling like mad?