Well, if you're getting Pokemon X/Y, you might as well get the X or Y version of the XL... (Makes perfect sense to me! LOL)
But, if you're still on the fence, then consider this... Get the original if you want the portability within your own pockets or get the XL if you want to keep getting the stylus the same way basically as with the original DS...
That, for me, is the true turning point in deciding between the two... (Either way, I still have NO idea why I'm planning to get a Y version of the XL when I get both Pokemon X/Y... when I already have the original 3DS...)