I went to see this in theaters. It was Miyazaki's worst film yet. I've only seen Nausicca, Howl's Moving Castle, Spirited Away and Mononoke, but all of those were considerably better than Ponyo. Maybe it's because the other movies I've seen weren't his kid movies, and Ponyo just went under my head.
The visuals were incredible as usual, but the story was downright boring. The characters fell flat at times too. Disney's original adaptation of The Little Mermaid is far superior.