I am also interested in this. In theory, the differences should lie in the quality of the re-sampling. I've read a lot of posts where people have not been pleased with the digital out signals of their sound cards because of the resampling from 44.1K to 48K.
I haven't done enough listening tests, but I am facing this same issue. I recently bought a Turtle Beach Audio Advantage Micro (TBAAM) which appears to resample everything to 48K, even when using the digital out. I then connect the TBAAM to my external DAC (Cambridge Audio 840C, which upsamples to 24-bit/384khz) using a Toslink cable. I would prefer to have a bit-perfect digital signal from my computer and let the 840C do all the DSP, upsampling, and D-A conversion.
But as alleyezon_d mentioned, I'm not sure how much difference this makes in reality. I'm going to do more listening tests with different software music players to see if they make a difference, before ditching the TBAAM for something bitperfect.