AB0 you are right and not much of a difference, a very high noisefloor on both cards.
But you dont just look at specs on sound cards. 16 bit, 24 bit, 32 bit, it was all recorded in 16 bit (as CD's are 16 bit)
And yeah, their are better sound cards than the soundblaster crap, the m-audio is not in the same line as it is a stero studio card.
However M-Audio revolutions are aimed at the gaming world, but I have never heard one. Turtle beach are great too and save you alot on the wallet.
Also how many of you know that Soundblaster (And Audigy) are creatives low end cards? Creative EMU is their high end.
btw +1 beer if we ever have a TF meet for diablo