Those in a completely different ballpark as far as performance goes (a way lower one). Not even comparable, let alone the whole ASIO thingy and so on.
Davros: numbers mean nothing, but the X-Fi is way better than Audigy (or any other card out there as of now) in every regard.
Btw, I use integrated audio right now and have no Creative card, but it is a nice piece of HW regardless
Except for the drivers, which is always the problem with Creative cards.