I'd say the Auzentech Forte as I have one and it's amazing for gaming. I also swapped out the OpAmp for a Burr Brown one and damn it sounds amazing. Plus, I don't know if you have super high end headphones or something, but the built in headphone amp is always a bonus.
To my knowledge, the Asus cards are more focused towards home theatre setups. I'm not saying they're bad for gaming, but I think an Auzentech card will do you better for gaming. Forte or Prelude, they're both good.