I posted a review in the book forum, but since we can use more traffic here:

I recently finished The Passage by Justin Cronin after seeing it recommended by Stephen King. It is a long (766 pages in hardcover) novel which is partly scientific thriller, and partly post-apocalyptic science fiction. In one respect it's a "vampire" story, but it's along the lines of The Strain and the earlier I Am Legend in that vamprism is given a scientific explanation, and the vampires are zombie-like monsters, not gentlefolk with fangs.

As I said, the book was long, and while there were parts of it that were very interesting, I did not think it was very elegantly brought together. Some sections seemed rushed, and the characters flat. Other points dragged with too much descriptive detail. For the record, Cronin is a fan of long paragraphs. It wasn't bad, exactly, but it was not one of those books I was always itching to get back to. It would be a ot easier to recommend if it were only 300 pages. As it is, keep in mind this book will be a big investment of your time.