Yes it has just as much EAX 5.0 capability as the x-fi, meaning it really doesn't but it comes close. Neither optimally support EAX 5.0, they use different means of simulating EAX 5.0. As for the other, its just vapor and means nothing.
People don't buy a sound card because of the features, they buy them because of the sound quality with the features a second issue. If you only care about features then the Asus DX isn't for you, but if you care at all for the sound quality then it is.