I would agree that the PS3 will get the bigger boost from FFXIII than the X360. But merely having it available on the 360 in the West will be a huge boon for X360 gamers.
So for the record:
FFXIII Japan:
PS3 > X360
FFXIII NA/PAL:
X360 > PS3
This will be a great boon for JRPG enthusiasts in countries that it's day and date, for the 360. If it's time exclusive in Japan for the PS3, obviously it'll still move huge bits of hardware for the PS3.
*However*, I do think we will see the X360 get a hardware boost in Japan from this. If the X360 does get FFXIII in Japan, I think we'll see quite a few gamers hop on board due to ToV, IU, and SO4 being exclusive on the X360, and TLR being time exclusive in Japan.
No matter how you cut it, this hurts Sony tremendously.
Back from the dead, I'm afraid.
