Have seen it in Japanese but not in english. Great visual effects & realistic character design ( God like i could see Reno's veins ) but they didn't have enough time to deepen the story. I'm sure we all got how depressed Cloud was over Aerith's (Aeris- why the hell did they change it?) death (and Zacks' too i suppose) and how weak he felt, but really that's all we got Cloud's wining, the kid's ( Kadaj- nothing personal) going on and on about reunion and a few good speaches from Tifa. Now advent children would have been a great TV series- the guys from Square Enix just didn't have time to cover all personages and develope the storyline so i guess they just made the best of it and that is another 3D action movie.
I also have the CG's from The Dirge of Cerberus - the first time i watched 'em was like watching the sequel .