(I have mixed feelings about this book so the review will take a while - assuming I don't just skip reviewing it)
Some quick thoughts: it has a more solid plot than its predecessor, although it is arguably more of a filler. The depiction of Artemis's mental illness is disrespectful at times (even though it is a made-up illness it shouldn't be made the bottom of jokes. It reveals a poor attitude towards the mentally ill).
The ending is a real downer. I quite liked the villain, in the sense that he was truly properly evil.