I hated it, actually, and I am a big Stephen King fan and I normally get a few kicks out of this type of genre. Alten's clearly a crazy person, though, and his 9/11 conspiracy theories are reprehensible. I might have been willing to give him some rope with that, if the book were well written, but it simply isn't. Honestly? This probably would have worked better as a movie.
I judge these books by a pretty simple criteria, which is "would the freshman in high school me have liked it?" And the answer is "No, he would have returned it to the library and seen what the new Dragonlance novel was."