I'm pretty much in agreeance with Ouch! on this subject. The first disk or so was brilliant, then the plot and character development just slipped majorly.

The soundtrack, despite what some people think, is pretty good (save a few tracks). It's defenately one of the best in terms of the extra arranged / piano /orchestrated (live) versions, IMO.

P.S. I have yet to play FF12 (releases 28th Feb here), so I can't compare it's story to that.