Remember that Final Fantasy is far, far bigger than any of the 360's JRPGs, and that FF is the best selling RPG in Americas ever, regardless of whether it is JRPG, SRPG or WRPG.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS