After a fairly enjoyable first book the series was pretty grotty right through. The series did improve again after the third book, but as for the last book: way too much filler. Sure, it was spectacular stuff that I'm sure will be well suited to the big screen, but I started by reading the end, read the start, and gave up. As always the writing style is mediocre at best, and I truly got fed up of the pointless hoops the characters were made to jump through. As for the characters themselves, their character changes inexplicably at almost random moments, particularly in that whole sequence when they've left their safehouse. In the end, an average series with some good ideas stiched together in arbitrary ways by means of bad writing.