I think I have read one other Chrestomanci book, but it has been a while. I think they are OK, but, for some reason, I am not really very fond of the parallel worlds plot device. I do like the idea of alternate histories, though, so it is somewhat puzzling to me that I don't care for the parallel worlds. I guess one thing I don't like is the characters traveling back and forth between all of these parallel worlds. It is too confusing - and leaves too many open questions - how do they get back and forth, how do they arrive just in the nick of time, how do they know which world to stop off in, etc.
Characters: I really got tired of Gwendolyn in Charmed Life. You are supposed to, but it got so annoying that I could hardly read those sections any more. I guess it reminds me too much of some of the students I get in not-so-great classes that I sub for. I found Eric a bit too passive, but still interesting. I liked Charles (Witch Week), but I would have liked a little bit more information about why he changed his mind at the last minute. Feeling sorry for Chrestomanci didn't feel quite strong enough to me.
Still, they were good reading and I think kids would enjoy them.