Let me make one thing clear: Vampire Knight is not fine literature. It is a known fact of science that most copies of To Kill a Mockingbird would rather go through the shredder than be put on the same shelf as a volume of Vampire Knight.
But that's okay, because Vampire Knight doesn't try to be fine literature.
Instead, it tries - quite successfully, in my humble opinion - to embrace its sparkly, melodramatic, red-and-black-soaked madness. The heroine Yuki finds herself torn (occasionally almost literally torn, skin-wise) between handsome guys of varying vampire-tude, with every chapter delivering a new revelation about who's a vampire and who knows about who's being a vampire and who didn't tell who about who's being a vampire when they really probably should have.
Confusing, perhaps, but deliciously confusing.
If this reminds you of another "teen vampires in love" series, you probably already know how you're going to feel about this manga. Readers not immediately turned off by the idea of gorgeous young bloodsuckers should take a look at Viz's preview of the first chapter.