I just finished the last of Phillip Pullman's Dark Materials books. I have to say all three were spellbinding and I ate them up.
The Subtle Knife is my favorite by far. If you are Lyra's fan you will love this book as I do. It is more of an in-depth look at our fair young heroine. This book brings in a new character as well. You wont want to put this book down. The vivid imagination from the author paints a scene that will keep the pages turning unnoticed as the movie plays in your head.
It was an alright book compared to The Golden Compass. The Golden Compass had such a high action pace compared to The Subtle Knife. I liked it, but since it was more "laid back", it took me forever to finish it. I'm a kind of reader where if it starts to bore me or it has not much action for so many pages(especially if you compare to the first book), my reading slows down.
However, if you are someone who likes to finish series, don't skip this book! Still a great read!
Also yes, the series leads to the end about killing God and all. I've read Philip Pullman was an atheist because he had religion pressed on him as a child. Really I think that if you don't want to read the last book because of the whole "killing God" thing. Then you probably shouldn't read the series at all. Not trying to be foul or anything, but I know a lot of Christians who read The Golden Compass and The Subtle Knife, and are afraid to finish the series. If you are one of those kinds of people, you probably should look into the book series before reading/finishing.