Yes...I know I am not a middle-schooler but with all the buzz about the book, I wanted to check it out for myself.
It was an enjoyable read: exciting, intriguing, with well developed characters. Never read about vampires before so that definitely made it different from my typical novel choices.
Would I let my middle schooler read the book? Nope. I would strongly discourage it. Although the main characters do not go beyond a few kisses, there is a lot of sensuality and longing. There is a lot of appeal and desire expressed through the senses and for these reasons, I would be concerned that it would prematurely awaken such desires in my kids. It's hard enough to hold fast to purity. Why commit to 400 pages that could only make that more difficult?
Tim Challies has an excellent and extensive book review that is worth checking out if you are interested in the specifics of the book.