ok this game is kinda old/new and on the PS2, which mine has been collecting dust for some time but I decided to fire it up again for this title. Now before you say that its just a remake of the GBA, you'd be right. HOWEVER, that GBA was pretty awesome way of doing the Kingdom Hearts in a portable way, not to mention turns it into something else other than a mindless button masher that KH1 and KH2 was.
The combat system, despite being card based, is pretty damn deep imo and forces a more strategic gameplay due to the cards number values (i.e.: A card with a value of 3 can be broken by a 4 card value, but a 0, which is basically an ace can break anything and be broken by anything). Another note that should be taken is this game is by no means slow paced, far from it, I haven't gotten far in the PS2 version but the later parts of the game actually have me scared at the difficulty considering the insane pacing of combat there was in the GBA version and that was an isometric view, its full 3D here.
So far its a good game, especially if you like KH, never got to play the original CoM, or never played Final Mix+ (which is where this game comes from), or want a reason to bust out the PS2 for those of us that don't have the all mighty original 60GB PS3.