Synchro-Mesh will not degrade the sound quality, only improve it, usually significantly. Just read all of the customer feedbacks on my audiocircle forum.
The resampling chip used is excellent. I have compared resampled tracks to native tracks and usually the resampled tracks sounds better using the SM because of the jitter reduction to extremely low levels, the galvanic isolation and the upsampling from 44.1 to 24/96. Upsampling to 24/96 causes the DAC to use a superior digital filter, with less audible artifacts.
Steve N.
Empirical Audio