Follow THIS LINK to read what I'm telling you right now, "Final Fantasy XIII" will come packaged as one Blu-Ray disc for the PlayStation 3 but likely three (if not four) discs for Xbox 360.
The link will also tell you the games will look pretty darned near identical visually.
To this I can only respond, who cares if "FF13," or any game, is on multiple discs? I've heard over the years how Sony loyalists treat this Xbox flaw as some "PlayStation will prevail!" rallying cry, but I just don't see it.
Why? Because "Final Fantasy" titles have a long and successful history of multiple discs. I've played all of them, and they've never bothered me in the least. Heck, "Final Fantasy VII" even incorporated the disc break into their storyline. Back in the day, the only thing more epic than the concept of Aeris — decade-old spoiler alert — dying was the fact that the moment marked the end of a whole disc. As me as a youngster, this combination was packed with more mythos than was previously humanly possible.
I, for one, will walk fearlessly forward on my way to playing "Final Fantasy XIII" on my Xbox, disc changes or no. If we're lucky, it might even add to the experience once again.