Aside from the book i give this a 8. After reading the books and then re-watching i have to give it a four! The director fell of the plot line terribly.
The main downfall of this series to me is that the director used the first book as a basis for the story line, then uses pretty much nothing of main importance from the remaining 3 books. The 4 books could have made into maybe a 4 season show. If he would of followed the plot line, almost to the key maybe with a little extra off the topic stuff made more money from 4 seasons then 6 mini-movies. I would have loved to see the fight between the leviathan and Aaron. Not only that but the final battle between Aaron and Verchiel. Hell in the book is not portrayed as place but a state of suffering/pain/anguish inside Lucifer. Lucifer was portrayed as antagonist from being to end in the show but in the book Lucifer started as a antagonist from his feelings of jealousy when later he became a protagonist by not letting the hell God gave to him as his punishment destroy humanity and angels alike.