It's hard to write a good book about a character that isn't truly likeable.
Nathaniel is out looking for revenge. That alone made it my kind of book. On top of that, Nathaniel's mood changes were authentic–IOW, rather like my 2 younger brothers.
What takes the book to the next level, though, is Bartimaeus, and the hilarious footnotes written in his POV.
He's just pure fun.
Do pick this one up. Bartimaeus will make you smile.