Compared to the television series the book is fluff - not as intense, because the visuals and the acting make the characters come to life. It's nice to read though, because you can hear the actors say the lines, especially Dexter's sister.
Rita, on the other hand, is dull in the book, because you only get Dexter's perspective and the same goes for many of the other characters - LaGuerta and Angel especially. The character of Doakes works quite well in the book, because Dexter recognizes him as a possible adversary and a threat.