Personally, I liked the movie better than I did the books. It had it's face-palm cheesy moments, of course, but I think the trees more than made up for it.
Seriously. The set was gorgeous, although the weird blue filter was out-of-place and annoying.
I think the movie did suffer from its being rushed out so quickly. In several scenes, the vampire's wires were visible (particularly Robs, in the scene where he's climbing trees for some random reason). The blurry-slow-motion-super-fast vampire! thing was kind of... odd, shall we say? Several of the minor lines were obviously incorrect ("ah! Kristen! Help!" anyone?) and several major lines, such as the famous "lion fell in love with the lamb" line were rushed and slurred together. Personally, I think Pattison and Stewart's open dislike of the series may have had something to do with this.
That being said, I think both of the main actors did an excellent job portraying the characters, Stewart especially. Movie-Bella actually does seem shy and awkward, as opposed to Book-Bella who, to me anyway, just seemed whiny. Movie-Edward was even almost relatable in his awkwardness, though, quite frankly, Pattison looks both revolting and creepy with the white paste all over his face, the greasy hair, and the lipstick.
The villains were introduced much earlier in the plot line, which was nice, mostly because I have a fetish for villains.
Overall the cinematography was decent- not great, and the blue filter was terrible- and relatively without flaws (I did not, for example, ever see the boom drop in from the top of the screen). I thought the soundtrack was oddly disjointed and out-of-place for most of the scenes, however.
I also did not like Stephenie Meyer's cameo. She blocked out the main characters, and the camera angle made her look much, much larger than she really is (don't get me wrong, I think Meyer's actually quite pretty. The angle was just supremely unflattering). It seemed very contrived and ego-stroking to me.
The movie left out or rushed several important points from the book; Jasper's power is not mentioned at all. The last few scenes with James are mashed together into a confusing thirty minutes or so, the sort of thing that leaves people who haven't read the books at a definite disadvantage. I think, also, that by cutting out much of Bella's monologuing, whining, and obsessing about Edward, the screenwriters showed Bella and Edward's relationship for what it was: incredibly fast, hardly any conversation, and based mostly on looks and a handful of interviews with each other. A lot of fans, from what I've seen, don't like this. It also makes the whole I've-been-watching-you-sleep thing seem creepier.
My overall impression of the movie? I enjoyed watching it with my free movie perks (cinema jobs are a wonderful thing), but it's not the sort of thing I would shell out nine bucks for, much less the exorbitant amount of money they're asking for the DVD now. Still, if you're a fan of Twilight I would certainly recommend it, if you can stomach the sight of Pattison's hair.