This one was definitely more entertaining than The Miserable Mill. I liked the setting a lot and the new characters were super interesting. I loved the new clue at the end, and now that the Quagmire triplets/twins have been introduced, I'm intrigued to see what will happen net with them.
I only read books 1-3 & 8 as a kid (don't ask why, I read series out of order all the time for some reason) so at this point my brain is trying to predict what's going to happen since I remember 8 pretty well.
Anyways I'd say this one was a hot 3.5 stars!