I love Miyazaki/Studio Ghibli movies for their imagery and their emotional breadth, and this didn't disappoint. I also love them for their strong plots with pro-environmental (for lack of a better description) elements. In this case, however, I thought the plot was a little muddled and many of the characters' motivations unclear. But that didn't bother me very much; I'd happily watch it a few dozen times more just for the nifty imagery.
They showed a preview for Neil Gaiman's and David McKean's MirrorMask. Sheesh, that looks weird. I love Neil Gaiman and can only tolerate David McKean in pretty small doses, but I'll probably go see it anyway.