Comparing SSRC High Precision and Sox 14.4 Very High Quality: http://src.infinitewave.ca/
Lower distortion and noise floor seems to be the only benefits with SOX. However, they are both at or below -130 db so I am not really sure what is gained in practice?
In the other tests at the site SSRC is either as good as or better than Sox.
The SoX VHQ SRC seems to have a lower noise floor, and less potential for aliasing than SSRC High Precision. (I assume Media Center is using high precision)
While something below -130dB should be inaudible on its own, assume that SSRC is 14dB worse than SoX.
That on its own is fine, but what happens when you are also stacking this with other processing which each raises the noise floor by 10dB or more.
Suddenly what should have been inaudible could now have an audible effect on playback.
While the reality is that this should be more of a theoretical change than an audible one, it's
possible that it could have an effect. Letting users choose between SSRC or SoX would also let them use SoX's other options such as Minimum Phase. (which
may be beneficial when upsampling to DSD)
But it sounds like it would be a lot of work to implement, so it would be low down on the list of priorities for Media Center's development.