A well written novel. While the setup takes its time in some places (though I was never impatient at any point), it picks up pace subtly until the end where you want to reach into the computer, grab it by the lapels and yell, "More, more, there must be more!"
I thoroughly enjoyed this book, particularly because it does a very good job of world building. It also manages to be something of an historical fiction/romance in a modern day setting with plenty of nerd details, no mean feat. The characterization is full and varied, with the strengths and weaknesses of each character leaving their imprint on the story.
Would I recommend this book to others? Oh yes.