Vulpix has more tails... Which is better for cuddling. That's all that matters.
But Gamefreak made the greatest choice in choosing Fennekin as the fire starter. I just hope his evolution line is as similar to Vulpix/Ninetales as Fennekin seems to be. I don't care about too similar of a Pokemon line. We've had it before now why not for a Pokemon line that actually looks good.