Probably the most jaw dropping expeience I've ever had with cables were the Nordost Valhalla. Stunning cables, though after time I found them too difficult to live with long term. They were so revealing that I found my listening sessions growing shorter due to listening fatigue. I still say they are the best demo cables in the world, but I wanted cables that I could listen to for hours everyday.
I found two other cables that I would say tie for the best for long term listening, IMHO. The Jade Audio Hybrid Gold and Stealth Indra, They are very different, the Stealth being almost as transparent as the Valhalla, but a bit more musical. The Jade being probably the most musical cable I've ever heard with incredible dimensionality.
Competitors? Far too many to even think about listing, sorry.