From what I understand it will be a darker version & VERY different from the Disney version. MTV has an article about it here.
If it's something that Kristen wants to do then I think she should. It'd be good to see her in a "bigger" movie compared to all the Indie films she's done. (Nothing wrong w/her doing indie films. I love that she still does them & loves to do them. I just think it would be nice to see her in a big movie after Twilight. Show all the haters she can act & do other movies.)