I've just finished this, and as soon as the last word finished I wanted to download the next in the series. It is quite simply fantastic. Large amounts of imaginative ideas, characters that I cared about, touching relationships, dark themes. After a slowish start, turned out to be one of the best books I've heard. My wife occasionally caught me stood stock still in the Kitchen as something particularly suspenseful happened.
Absolutely fabulous book - not one to put a big smile on your face, but does ask some big questions. I found it quite difficult to read at times due to the trials and tribulations that some of the characters go through.
The narrator is absolutely fabulous, I really can't say enough good things about him, every voice is differentiated, and at times it's difficult to believe they're all coming from one person. I'd personally have him do all books from now on!
Again, the narration is fantastic by humphrey bower, he is the best I've come across for narration, each character immediately clear.
The best description I can come up with for this trilogy is suggest you imagine the 'His Dark Materials' trilogy combined with the tone of 'The Road'.
That description is intended as a compliment as I enjoyed both of those immensely. Heartily recommend this trilogy.