Its like Hugh's playboy bunnies: fun to look at as long as no one opens their mouth.
Visually, its stunning. If you've been using Spirits Within as your CGI showcase, this serves as a much better alternative with much less chance of putting your audience to sleep. Although if you're not a huge fan of anime, the animation may get to you after a while. Some of the moves are down right laughable (anyone else want to toss cloud up in the air...anyone?)
The voices range from adequate to horrible. Whoever supplies Barret's king fisher accent set his race back a decade or so. I'm not sure what I expected Red XIII to sound like, but certainly not like a 5th member of the ninja turtles. Yuffie's voice produced a desire to strangle, though I guess that's on par for the character.
The sound effects were ok on the Dolby Digital setup, but on several occasions not everything that happened on screen produced sound as it should have.
As for the plot, it didn't expand or wrap up anything from the game.
Despite all the unkind words I've used, I'd still recommend the movie for anyone that played the game, loved the game, and is looking for that nostalgic twinge when the new Highwind makes its appearance. And how can you not recommend a movie with a Bahamut summons?