Can also attest the effectiveness of the digital cable.
Having experimented with a small number of digital coax cables I'd drawn the conclusion that there was little benefit moving from modest to fairly extreme. My digital had a slightly dark, heavy character that I attributed to the Marantz house sound. Sounded more than adequate with a noticeable character next to analogue.
Introducing Paul's SL-D coax made a substantial difference, the sound opened out and largely lost the dark, heavy character, far more natural sounding. Colour me surprised, I bought one.
If the other digital cables share this quality and reports suggest they do then well worth investigating