Wow, this is petty late for me to be responding.
I have not heard the interconnects, only the power cords and speaker cable.
I would find it hard, having owned the Delta, to believe it outperforms ANY ZiTron cable. I had a Delta, Alpha and Sigma, all of the most recent incarnations.
The Delta simply did not have the "bloom" and the realism of the ZiTron cables. That was the first time I’d bought a Shunyata that I admired - but didn’t like. I sold that.
I have recently realized that the current Alpha line was/is (?) slightly "lean" in its sound.
About the Sigma NR, no reservations at all. I tested it in a dealer showroom against the Nordost Valhalla power cord, and, given that there was no time for the Shunyata to "settle," I would say the Shunyata outperforms the Valhalla 2 power cords, which cost 4x as much as the Shunyata. And this on an Audio Research based integrated amp, wired all the way thru with Nordost, Zanden CD player, Wilson speakers (I think! It was 2 years ago). Only one Sigma was inserted into the system on the CD setup.
Again, the Delta is nice, but it is not a ZiTron (which is why it is priced so low ($700). Usually, Shunyata’s better cables were - for years - $995 for a Python, but with the new line, The Delta is $700, the Alpha, $1500, and the Sigma close to $2800.00.
I’d also pay attention to the upper bass/lower midrange area. Some say it is merely "flat". I disagree strongly. It is just a bit recessed, causing the whole "power range" (100-400) to be just slightly...less powerful. And the instruments seems slightly bleached in those frequencies.
I could be wrong, so try it for yourself.
