It may be that this will be the last part of the Haruhi Suzumiya story to be produced, given the uproar in Japan over voice actress Aya Hirano's private life. I hope not - I have truly enjoyed the series, even Endless Eight, and there are many more excellent stories in the light novel series of the same name. But if this is the end, this is a fantastic way for it to go out.
The story is paced beautifully, with the situation surrounding protagonist Kyon and his complete bewilderment at the change in his life being revealed step by careful step. I for one am glad they made the choice to have a long running time, just so the pace could be right - there have been too many instances of books being turned into films where the pacing was far too rushed, where it seemed like a breathless rush from one ste piece to another. Not here. The set-up of the particular fix in which Kyon finds himself, the solution to it and the twist in the tail are all given time to develop.
What else? The characterisation is excellent, especially of Yuki Nagato and Kyon - most of the story revolves round them, with the others playing lesser roles - though Haruhi herself is very, very conspicuous by her absence for a large part of the story. The humour is gentle, the artwork fantastic and the scripting of the choice that Kyon has to make - whether to accept what the world has become or turn it back to the way it had been - is presented beautifully.
The one warning note I would sound (and I am not the first to make this point by any means) - don't watch the film if you haven't seen the preceding anime series - I counted about 10 direct references to various episodes, not to mention understanding the characters - you will end up mightily confused. But for the vast majority, if not all, of Haruhi fans, this is a winner.