I wouldn't bother with an external usb audio interface for output only apps - the real value is the input options you get and the portability. Edirol makes good stuff, and although I have never used this interface, I would suspect it will work great with the proper drivers for your OS. It is a reputable company and looks like it will be around for the long haul. Anyway, you really can't compare a built-in sound card intended mostly for output to an external usb audio interface mostly intended for input. The usb will be so much better.
Good luck.