I finally saw this movie over the summer - I bought the DVD for $4 from a closing Blockbuster and watched it with some friends. It's only been a few months, but I find I don't remember a whole lot of it. Maybe it wasn't as memorable, or I'm just more cynical since I didn't the see movie as a kid like I did with the first three.
I think this was the first movie to incorporate CGI, and I found it very weird and jarring. Good on them for trying, I suppose, but it just didn't fit, especially CGI Suicune. Only making the evil plant-Celebi-thing CGI would make sense - it's unnatural, thus it looks weird and jarring, that makes sense. But not Suicune.
I knew that Sammy was Professor Oak before years before seeing the movie, so there wasn't any pleasant surprise in it for me. Rather, I found it a little weird that Oak still sees Ash as a close friend even though Ash hardly knows the older Samuel. I wonder if he should have eventually told Ash about it after Ash meets Celebi (a la Back to the Future), but the whole situation just gives me creepy vibes, so I guess it's better that Ash doesn't know.
For a Pokemon movie, it was all right.
~Psychic