I'm quite surprised to see people being so dismissive of Vesperia PS3. I actually thought it was a pretty big enhancement, myself. Two extra fully playable characters, full voices for the entire script, extra costumes, extra skills, extra scenes, extra skits, extra music, extra bosses, extra areas... Short of actually revamping significant chunks of the game, I don't really see what other bonuses they could have added.
Of course it's kind of overdramatic to suggest that the 360 version is crippled and worthless thanks to the additions that the PS3 has, but they're not exactly insignificant either, and I think it's a real stretch to compare Vesperia PS3 to SotN Saturn or ToS PS2. SotN's extra areas were practically unfinished, and ToS was such a technical mess compared to its Gamecube counterpart that whatever small additions it brought to the table did little to change the fact that it was pretty objectively the inferior version of the game. Vesperia, on the other hand, adds some fairly substantial extra content at the cost of very little noticeable technical performance. Enough to justify calling the 360 version a beta? Not really. But certainly enough that, were both games available and comprehensible to someone who owned both consoles, I'd see little reason to recommend the 360 one.
Anyway, I'm kind of relieved now that I didn't buy Xillia last month after all. Though it's sort of sad that it's getting to the point with some companies where you stand to lose rather than gain by being an early adopter of a game. Especially in the age of DLC and patches, when there's rarely a need to do a full re-release. Fingers crossed that they opt for DLC for the sake of those who bought it on release.