Very mixed bag.
I just began playing this game again seeing as I never got around to finishing it despite pouring over 60 hours into it.
I counted down the days to this title, nervous of the newly created battle system but trusting in the sureness of a fabulous, immersive story populated with memorable characters.
What I actually received was somewhat different.
As a veteran of Final Fantasies since the very first, I was shocked by the lack of depth in the story and ultimate blandness of it as a whole. There are very few motivating factors driving you toward your next goal throughout the game, and in general the motivation of the cast can be described as a typical "overthrow the evil empire" plot line not unlike Star Wars.
The characters... Such a mixed bag. The two main characters of Vaan and Penelo are incredibly boring and can even become somewhat annoying throughout the story. The voice acting for Vaan is absolutely terrible and uninspired, and throughout the game I felt myself wishing that Blathier or Basch were cast as the main character rather than Vaan.
On the other hand, there are some fabulously fleshed out and incredibly human characters. My two personal favorites are Balthier-- just like everybody else-- and Gabranth. Both are driven by very personal conflicts and their motivations feel very real to me, and probably to most everybody playing the game. Balthier is wonderfully-- perfectly, even-- voiced and his one-liners make him instantly likable. I cannot imagine Balthier being voiced by anyone else. The actor that plays him does a stunning job, so much so that it should be recognized as one of the great voice performances in video game history. Gabranth, in my opinion should have taken an even larger seat as the main villain seeing as how Vayne is universally convicted at this point (two years after the game's release) as one one of the worst Final Fantasy villains ever.
Ultimately the characters lack sufficient development and even backstory save for very few like Balthier, Gabranth, and even more minor characters like Reddas. The characters that are developed and given an adequate backstory, however, are immediately likable and are pretty much all that drove me to play the game along with the excellent combat system.
Combat is a dream in this game. It's a lot of fun. I have historically hated grinding in RPGs, but in this game I find myself doing it even when it isn't needed just because it's so fun to tweak gambits and let your characters do what you specify without you having to tell them each time. The gambit system sounded fishy when it was first mentioned to the video game media, but it works beautifully and makes me hope that they bring it back for Final Fantasy XIII (very doubtful, though).
All-in-all, this game is worth playing just for the combat system. If you're an RPG freak, you'll no doubt be disappointed by the lackluster plot and filler-quality main character, but this game should be played through nonetheless.