Also, I have to say that the ending of the book didn't really appeal to my need for completion. I'm the kind of guy that, if I can get it, wants every loose end tied up nicely. However, given the way the novel ended, I can understand that Powers was going by the old addage, "In late, out early." The main conflict was finished, and everything else after that couldn't have possibly been as exciting, so he gave us a little bit of closure and dropped the curtain. I don't really think tying up all the loose ends would have made it a better novel, and it certainly could have made it worse.
Overall, I'd say that if you're a fan of high seas action, dark voodoo style magic, or Monkey Island (yes, the creator of that game sites this as a big influence) you owe it to yourself to give this book a go. You'll enjoy the characters, and you'll feel super-informed when you go to see Pirates 4 in 2011. For me, this book was an excellent way to discover Tim Powers. Obviously he has other novels that have met with greater critical acclaim, but this was fun, well written and enjoyable. This book definitely convinced me that I've been missing out on a great writer.
Final Score: 8.5/10. An exciting, well paced swashbuckling adventure that's deserving of a movie all its own, but I guess Pirates 4 is the next best thing.