The distortion and S/N of modern D/A chips is much improved over that of 10 years ago. Addition of reclockers on the S/PDIF inputs has made inexpensive DAC's better, but I don't like it on high-end DAC's.
Some of the biggest improvements have been in the computer interfaces, including USB and Ethernet. These lower jitter significantly compared to transports. It is hit-and-miss though because many of these are designed by third-parties and achieving really low jitter levels is not trivial.
Steve N.
Empirical Audio