Finished the game. I think I'm one of about five people on the internet that loves XIII unabashedly. It got rid of everything I loathe in jRPGs - infrequent save points, "resetting" to the last save point after a party death, slow-ass combat (I like turn-based, but it can be really fuckin' slow, eg. Lost Odyssey and feeling obliged to change rings every second goddamn turn. In XIII nobody's ever just standing around waiting), pointless NPC interactions that are just there to beef up play hours, etc.
It sure is a flawed game, though. The cast is 50% awesome (Lightning, Sazh, Fang) and 50% groan-worthy (particularly Snow) but it's fairly decent as far as modern FF games go...which isn't really a compliment. Exploration is, obviously, linear. The playable cast needed to be bigger; I'd have liked a few extra non-essential folk just to provide some variety. The voice-acting was top-notch for an imported RPG, though optional Japanese voices would have been nice. The storyline made sense to me but there's a lot that should have been explained better - I get the feeling a XIII-2 will be released, I only hope it's better than the other FF sequels Squeenix have released.
Additional observation: as far as Tetsuya Nomura goes, the character designs were surprisingly restrained.