Is it loyal to the book? I haven't read this one, I'll get on it.
Best character: Ms Eglantine Price rocks. She is and always will be the pinnacle of Angela Lansbury's roles. Also, my cat Cosmic Creepers was named by her.
But is it art? The animated sequences are pretty sappy, but very similar to Mary Poppins. (This film is often called the ugly stepsister of Mary Poppins, but I prefer it.) The live action stuff is kind of dark and grimey, but appropriately so. And the special effects aren't too shabby considering how old this film is.
Major Flaws: The edition I have has the extended scenes put back in, most are no problem at all but the delightful Portobello Road song has been extended to a dance sequence that might just be longer than the monarchy of Luis Filipe of Portugal. (Look that up.)
Best character: ...must say I'm a little biased towards any Hugh Jackman character.
But is it art? EPIC in the truest sense, it tries to recapture the feel of old Hollywood epics and succeeds spectacularly. I am of the opinion that this film needs the biggest screen you can find to properly enjoy.
Major Flaws: The first twenty minutes are necessary plot development the first time you see it. But I skip them after that. Also the first viewing will make you think that you've reached the ending a few times before you actually do.