To put it nicely: Not up to par.
I greatly enjoyed his previous books and I eagerly anticipated reading "Hannibal." Now all I can say after finishing the book is, "What! " The book had its good moments but there were long periods that lulled me to sleep. I felt that the author betrayed the two great characters of Lecter & Starling with his awful conclusion, and in doing so, betrayed the fans that built his fame. Lecter's macabre mystique and power & Starling's balance of strength and vulnerability? - the authors throws all of this out in this book like used kleenex. I would say it ranked with "Godfather III" in disappointing sequels. If you are a fan of Silence of the Lambs, my advice is: read the first half of Hannibal, then make up your own ending - you couldn't do any worse.