I enjoyed it, and my wife (one of those few people who hasn't read the book) enjoyed it. It was a nice date for us away from the kids. Overall the movied stayed tight to what I remembered within the book and my only complaint would be the change in pacing.
The book was more of an adrenaline rush for me - you were (almost? hehe) always wondering what was coming next and constantly being pushed up against new information as you tried to unravel what was going on. For whatever reason, that speed didn't translate onto the big screen.
I still want a cryptex! *laughs*