Western no doubt about thanks to Mass Effect, but considering that almost all JRPGs (Final Fantasy XIII, the Last Remnant, Eternal Sonata and I'm willing to bet that Star Ocean and Tales of Vespera will end up on the PS3 as well) are going on both the Xbox 360 and Playstation 3 as multiplatform I'd say that they're equal on the JRPG front.
Yeah, i bet that Star Ocean is going to the PS3 sooner or later, in fact, in the Microsoft press conference, when of the showing of the SquareEnix games, the only game that appeared as exclusive was Infinite Undiscovery.
But, at the same time, if the game was going to the PS3, Sony would have already announced it, to take the thunder off Microsoft.
So, my call is, at this time, is still undecided if the game is going to the PS3 or not, SE might be waiting to see how the game is going to fair on the 360.
Tales of Vesperia i don´t believe, but i do believe another "Tales of" game exclusive for the Sony console.
But, as of now, there are no JRPG on the PS3, so the thunder still belongs to the 360.
Everything the PS3 is going to have is or will be on the 360 too, and more (Infinite Undiscovery).
But Sony as a big card on their side, Level 5 never made a game for the Xbox, they work closely with Sony and they are a very good dev.
Dark Cloud 3 is a big exclusive to have.