I'm going to be civil about this, I am not a fan of Twilight, the story sounded interesting at first, a few friends at college were talking about it before it got outrageously popular, I said "what is this vampire book you speak of?" and "from the sounds of things I prefer the werewolf..." I started reading the first book and had to put it down after a few chapters but got a summary from a Twihard friend of mine.
The Writing
The writing is average at best, I'd rather class it as poor. The style of writing is boring and lacking, the tone Bella uses is monotonous and depressing, mind numbingly so. The lexis is verging on dead, especially adjectives regarding Edward, it's the same thing over and over and is just so tedious it physically hurt to read it. It was something akin to a badly written fanfic, I was surprised there were no glaringly bad spelling errors in what I read.
The Characters
The characters are lacking in depth, those who are more obscure have deeper personalities than the main characters. Bella is a boring girl who whines relentlessly about not liking a place, she thinks she isn't pretty, she's thinks she isn't smart, she is Mary-Sue kind of clumsy, you know the type, she does something stupid and accidental, if it was a super hero story she'd accidentally save the world from a nuclear missile hidden in her school or something equally bizarre.
Edward is "perfect", if you can consider someone who at one point is disgusted by Bella, and then a half-arc later is practically trying to mount her and declaring his love for her "perfect". He is just as monotone as Bella and thinks he's a monster, I want to call this backwards Frankenstein's Monster syndrome, as he needs to be convinced by someone he at least has urges to kill that he isn't a monster (grammar failed somewhere in that sentence). How that relates to Frankenstein's Monster is the monster went from "but I want to be normal" to "you all think I'm a monster so I'm going to be one", now reverse that and chuck some glitter at the monster and you've got Edward, albeit lumpy and not as grumpy.
The Story
It's lacking in direct plot, in fact, the actual plot doesn't come into the story until about 2/3 of the way in, and then it only lasts for a few chapters before everything is as boring and seemingly normal as possible. This occurs in most if not all of the books I believe.
Over all, not much to say on the story, it's just not that much of a story.
The Sub-Content
It romanticises all of the wrong things, stalking and vague paedophilia are the ones I believe stand out too much.
Stalking: if you think it's romantic for Edward to show up to save Bella every 20 seconds, that's fine, if you think it's romantic and normal for Edward to follow her around covertly then sit in her room and gawp at her whilst she's sleeping, you might want to seek professional help or look at the context in which you are romanticising this.
Paedophilia: Jacob... oh Jacob... He cannot have Bella, so he settles for the next best thing, imprinting on her child, acting all fatherly or brotherly or something towards her, that's okay, that's fine, but waiting for it to prematurely age and be a teenager when she's still a hell spawn mutant baby thing, then making a move on her, that is not fine, that is nasty and wrong on so many levels, yet so many can't see that.
I suppose really my issues with the "romanticism" are somewhat out of context, but they are still there... Oh but there is more on the dodgy moral values of SMeyer and her characters, I just can't remember them as I haven't actually talked about the books and my indepth issues with them in quite a while...
Edit
I'm a guy, I'm gay, I'm still a teen (barely... 20 soon = do not want), I generally like reading, I just can't stand Twilight. The hype didn't help.