Which of these two cards is better?

i'd go with the Auzentech to be honest, the spdif and optical can be very useful especially for both 7.1 and exporting digital audio if you're sound editing.

That said, the second card is EAX2.0 compatible, which will be better for gaming.

The first card is better hardware wise, as it seems to be more geared towards sound quality/editing, while the second seems to be more for gaming so it's really a toss up what you need it for. Id say if you pump an extra $20 or so though you'll get a card that'll do both adequately. But I think the deciding factor should be what you intend it for and what you need to connect it to, if you're speakers support spdif or optical, go with the first.

Make sure you buy a card intended for sound creation
the X-plosion is a good card a friend of mine has one but i don't think its suited for your purposes according to Auzentech

http://www.auzentech.com/site/support/comparison.php

i have a Forte and right now they are very affordable $100 at a few sites