I loved this.
I think the only problem was that there were so many story lines that I occasionally lost track of who was who and who was doing what where. It took a long time to get into the action, too, though I think in retrospect I appreciate the buildup and the mystery, wondering what was going on. I will admit to having to reference a Wikipedia page when I set the book down for a day or two to remember exactly what had happened and where I was in the book.
On that note, WOW, is Hamilton good at foreshadowing. Color me impressed -- things that were happening or even just ancillary to the story in the first chapter were insanely important in the last.