The reviews I've read of the AuzenTech suggested that a common issue was driver matureness. The AuzenTech does give you SPDIF Optical out, a feature you have to pay for in the SoundBlaster lines. ...but if it were me, I'd probably go with the Audidgy 2ZS as its drivers ARE mature and the SoundBlaster lines are more widely supported for games, should you ever delve into that.
Does soundcard drivers have significant effect on sound quality? I'm real angry cause it took me so long to get every component to the computer. Now it looks like I would have to ebay it off and order and wait for the Audigy 2Zs.