There is a BIG difference in construction between Purist and Cardas products. Most Cardas products use their 'Golden Mean' system of windings, which at least in terms of construction, means MULTIPLE strands of wire -- making their cable HIGHLY CAPACITIVE. In some systems, and especially when used with electostatic speakers, this will kill detail, and can result in what some people complain is a soft/warm/round characteristic "Cardas sound". This may or may not be a problem in some systems -- especially those using high efficiency speakers and low output amplifiers. Purist products use a minimal number of conductors, with their solid core conductor models having the lowest impedance -- but all their products will bring out the detail in those systems where that's what the owner is after. I have A-B'd full Nordost (Valhalla) cabling vs. full Purist (Venustas) cabling in my (very articulate) system and found the Venustas to be the most balanced and natural sounding IN MY SYSTEM! Nordost product might help "liven up" a different system that was sounding perhaps a little "too dark" or lacking detail?
Once again, I want to restate my conclusion -- after a lifetime of listening to all kinds of systems + cabling -- that I now believe that whatever brand/model cable one gravitates toward, the optimum result (and best performance overall) will be had by using the SAME CABLE (both model and manufacturer) throughout the system. In other words, DON'T TRY AND PICK THE "BEST REVIEWED" CABLE FOR EACH FUNCTION IN THE SYSTEM. This (probably) works for the same reason that all the connective tissue in our body is made of the same flesh ;~))