Buy this movie without hesitation. It's wonderful, magical, exciting, and rounds up the trilogy in the best way possible.
The guy who wrote the review that this film is wearing a little thin, is wearing thin himself. Many trilogies and sequels should hope to be only fraction of this movie. The writing, the animation, all top notch, it adds new stuff to characters you already know so well.
Enjoy it, if possible on blu ray because it looks absolutely amazing. And although the last part of the series, it'll fill your heart with sheer joy and warmth. Highly recommended!!