Cardas Golden Reference is definitely warmer than Tara Labs Decade. I know, I've owned them both. Yes, the CGR has more detail than other Cardas cables, but I still would say it's on the warm side. The Cardas Neutral Reference is the most, well, neutral cable in the Cardas line. I don't think any Cardas offering will be a step up from your PAD Venustas though. I actually preffered the Jena Lab cables, Symphony and Valkyre, over the Cardas Golden Reference, though the JL's are also on the warm side of neutral.
I would say the TL Decade has more detail than any Cardas cables I've heard, yet never sounded harsh or bright. I actually prefferred the Decade over the Air 1 series. The One is much better though.
I haven't heard the Synergestic Desiner's or Shunyata cables yet, so I can not comment.