I have recently upgraded from Reference speaker cable to Nite series and the improvement was excellent in all areas.
It seems as if the volume went up 3db, probably due to the ultra low noise floor. Bass is tighter and fuller with great definition. My WATT/PUPPY combo has no boom in the mid and lower bass any longer, acoustic and electric bass is much more organic sounding. Great separation of instruments with air and correct placement in soundstage.
I experience absolutely no fatigue from long listening sessions, the Wilson's can be fatiguing with the wrong cables and associated components. The midrange and highs are crystal clear, exposing details never heard on my system before with familiar material. The music just explodes from the speakers when called for, great dynamics, from delicate whispers to surging crescendos.
I usually don't like to be so enthusiastic, but these cables warrant the highest praise, in my opinion. I have had, in my system MIT, Transparent Ultra, Mapleshade Double Helix, Harmonic Tech Pro 9 and Truthlink, and TMC(very good for the price), and the VD cables are in another league.
I have always tried to use the same brand cable and IC's when possible, finding more coherence than mix and match.
I now have all VD power cords, IC's and speaker cable, mixing only series. Power 3 and Audition PC's, Audition and Reference IC's and Nite speaker cable, all cryo treated.