After testing various digital cables between the BDP-1 and BDA-1 over the last year, I settled on the horribly named "Purist Audio Design Aqueous Aureus -Praesto Revision (AES/EBU)". It was the best match for my all SS system with ribbon tweeters. The Purist Audio cable was darker and superior tonally than the other cables I tested, while maintaining plenty of inner detail.
The Purist Audio cable may not be as good of a match for someone using all tubes and it is normally quite a bit more more money than the nearly as good Morrow Audio and Wywires digital cables (I received a decent discount on the Purist cable). I decided to hang onto the Morrow Audio DIG4 since I plan on getting a new amp next year - just in case it might have better synergy with the new amp.
The Morrow Audio DIG4 and Wywires LITESPD digital cables might be pretty close to each other, but I didn't have them in house at the same time and wasn’t able to compare them to each other. From memory I believe the Morrow Audio cable was a step above the Wywires cable.
Cables tested (somewhat in order of preference since I didn't test all of them at once): Morrow Audio DIG4 (XLR), Wywires LITESPD (BNC), Wireworld Gold Starlight 5 (AES/EBU), Audioquest Hawk Eye (RCA with BNC adapters), Soundoctor (AES/EBU), Monster M1000 (RCA with BNC adapters), Blue Jeans (BNC - Belden 1694A), Audioquest VDM-X (RCA with BNC adapters).
-Greg