Personally, I tried switching from a Creative X-Fi Titanium (the PCI-E version) to an Asus Xonar DX, but so far am unimpressed to the point that I'm going back to the X-Fi (which was a big disappointment, given how crappy the Creative drivers/support are... thankfully the daniel_k drivers help).
To elaborate... I use Tritton AX 720 headphones which require Dolby Digital (Live). Although the Xonar DX supports it, it has an obnoxious habit of popping whenever starting a new application with sound. Also, in some (new!) games there is a really weird/distracting echo, like the person speaking is in a small room... this happens to great extent to me in Dragon Age, and is actually really annoying.
In any case, I love Asus in general and would really love to use/support their product, but for some reason the Creative's DDL just works and sounds great, where the Asus has some issues.
Note that I haven't tried analog connections since I'm using the Trittons...
In any case, to the OP, it's all up to you really. Check some reviews, but just try something. If you don't like it, return it for something else.