Have been listening to these over two days now. The Copper is extremely smooth, but I prefer the Silver - more open, better extension at both ends, and image projects forwards. Copper can make harsh songs sound softer. I generally think the cables are rolling it off slightly at the top, because both opera and classical the extreme highs seem a bit rolled off. Very musical cables, draws me in to the music. My usual cables were Virtual Dynamics, I might slightly prefer Graditech, not sure of paying the premium for it though.
You can use copper, stranded copper, silver, mix and match, biwire, or put say, copper at the back of the silver and chain them up. Lots of play opportunities there, but if I were to get them, would probably use silver for most music