Shames me to say, I only just watched this movie for the first time last week. I loved it instantly, the art, the animation and music was amazing. I was then hoping there would be an artbook and fortunately it seems like the more art driven movies are always supplemented by artbooks.
My book was the hardback version, I try to always get hardback, I think in the long run they will last longer. And this one seems to be of good quality. There are lots of great artwork in the form of concepts, storyboard and some mood pictures. As this is a 3D animation, I do think the 3D artists are not represented here adequately. Some renders of their pre-production final sculpts or wires in whatever 3D scultping modeling package they use wouldn't have gone amiss.
Overall this is a good book, lots of pictures and a good balance with the right amount of accompanying text. A fine addition to my collection of artbooks ^_^'