This book doesn't end, so much as stop. Nothing is resolved in The Subtle Knife and you are left with a cliff hanger. So, if you read this book, plan on reading book three immediately afterwards.
In general the author is not a good writer. More like a philosopher trying to write fiction. The descriptions are poor, it's plot heavy and not very emotional. That all being said, as a lover of philosophy, I have enjoyed books I and II in the trilogy and I will go on to read book III.
The author does have a good imagination. The ideas presented are interesting and the book works on a symbolic level. He has the ability to make surreal situations seem normal. I'm looking forward to see how the major conflict all works out.