Having had the HDT-1x for a few years, I am very impressed with the sound quality. The optical out is iffy with my setup (audio drop-outs) but the RCA out is 90% the sound quality and is rock steady. In the original unit I had, the optical out quit completely, it was out of warranty but a call into Sangean turned out to be very helpful- they took my old unit back and sent me a new/old stock unit, all I had to do was pay shipping.
It's always cool to hear the analog source going until the HD kicks in (when first turning on), the difference in SQ is quite stark.
Interested to know if anyone has gone form this model to the 20? Differences?