I started reading it a couple of days ago on a dare (I was somewhat curious anyway, to be honest). I only read it at school and it's a good time-waster. I have mixed feelings on it. On one hand, it's not that poorly written and I enjoyed Cullen's family story (probably the only part of the book I can say I actually liked, but I'm not finished reading it yet), but on the other I find Meyer's obsession with physical beauty and the relationships between Bella & Ed/ Bella & Charlie/ Bella & her mother all to be pretty bad. In Edward's case because it is really hard not to interpret it as abusive, in Charlie's case because of the way she takes care of him like a goddamn wife--I actually found the relationship a bit creepy at times, but mostly I felt bad that she sort of treated him like shit even with all the things she did for him, and in the case of her mother... there's nothing there. I mean she describes her as her best friend but makes no effort to communicate with her on any but the barest level.
The sparkly thing was stupid, as was the whole Edward-with-his-shirt-unbuttoned scene. But I guess this book is a romance novel, so I guess I should expect it.
The very brief mentions of religion generally bother me because I can't read them without thinking that Meyer is promoting her religion. Carlisle seeems like a genuinely interesting character, however. (He was a priest before becoming a vampire, for those who aren't going to read it/ haven't yet)
On that note, most of her characters are boring and two-dimensional. Edward might be able to read minds, but who couldn't in a world like that?
Bella's mention of an "estrogen rush" during her girl's night out made me cringe with You Fail At Biology Forever (I actually joined tvtropes just to add that bit)
I honestly just can't stand Bella in general.
Meyer is pretty heavy with a thesaurus, but it's only gotten on my nerves a couple of times.
It is not, however, as bad as I thought it would be. I can read it and actually get somewhat into it... but I just can't immerse myself completely, it just has too many flaws. I don't think I could read it without a conscious effort, honestly.