I read this to my daughter, Celyn (10), who is too disabled to read books by herself. 
 I had seen some of the anime film version years ago but remembered basically nothing of it. 
 I found the whole thing original and refreshing. The point of view character (Sophie) is engaging and no-nonsense with a very capable can-do attitude. The story moves along at a good pace and the whole moving castle / multiple doors thing is a great idea and used well. 
 The Welsh connection is well-played, and the continuing reveals keep everything interesting. 
 My only complaint is that the end seemed rather tortured with so many story-lines converging in ways that felt rather unsatisfying / hard to believe. The (view spoiler)[ Miss Angorian (hide spoiler)] part, for example, seemed to come out of left-field and made very little sense to me. 
 If I were a touch harsher then that ending would pull this down to a 4*. But Celyn loved it. I enjoyed reading it. And I'm in a good mood. So 5*. 
 I can see why it's a classic, and if you have a 10 year old, point them at it! We may well pursue the author's other works. 
 Edit: We've now finished the trilogy! 
 Join my 3-emails-a-year newsletter #prizes 
 ..