@lollipopguild - I currently use the silver diamond and prior to that, have had the ultra black, silversmith fidelium, and Ansuz c2 speaker cables in the same system and room. Right before I switched to the tellurium silver diamonds, I had the duelund v3 which is an incredibly good speaker cable for its price, which, with ETI brio connectors, just falls under the price for the silversmith fideliums. By incredibly good, I do mean the duelunds better all the others. It equals the fideliums in relation to timbre and air, with a touch better depth of soundstage, and with noticeably more solid and nuanced bass. I switched to the silver diamond only because there was a level of realism to these that I could not live without, but would not have changed the duelund v3 otherwise. If you can afford the duelunds, I would recommend them over even the ultra blacks.
Do understand that my comments are specifically in the context of my system and room - I have extremely good power supply, use a 19wpc tube amplifier, and a full range single driver speaker.
In friendship - kevin