I do have to say that I'm a big Kristen Stewart fan, and it's getting kind of irritating that people rip on her for every concivable indescretion they can think up(blinking, not enough emotion, etc-have these guys even read the books as they're in Bella's POV and Kristen has to interpret what Bella is feeling/saying/doing?!). I think that people are jealous of her for working with Rob and Taylor, and that she's so well liked as a person and friend by most of the cast and crew, all of whom have only have said good of her.
From an interview with Chris Weitz: -
"Do you think Kristen evolved as an actor in this movie?
I’m not sure she evolved as much as she had room to run. She’s a thoroughbred as far as actors go. To me, she can do know wrong. The experience of working with her and the caliber of work she was doing was pretty extraordinary. Let’s put aside girl in love with a vampire, her ability to manifest these emotions below the surface, above the surface just to get things right. She’s extraordinarily exacting of herself and in those moments where I was able to give her the room to do that are things I’m very proud of. That’s a high point."
And I think that ^ sums it up. Kristen is amazing. Some people were saying that she didn't cry in the movie, and your right, beacuse she did more than that. Anyone could just break into hysterics and make a scene. It takes a lot more to actually show the emotions of what she was feeling.