Well, for the $$ the Auzen Prelude is the better card, especially if you don't need the EP's breakout box. ...but Creative's current drivers are quite a bit better than Auzentech's current drivers in Vista (if you're using that OS).
If XP is still your OS, I'd say save the money and go with the better card, which is the Prelude.
...hope you're feeding something better than PC speakers with either choice though, because, if not, both cards are overkill, IMO.