I own 4 pairs of interconnects:
Two pairs of free in-the-box
A pair Wireworld Oasis III, cost me about ? 80 (£60)
A pair Wireworld Oasis V, cost me about ? 100 (£80)
Both Wireworlds look nice, both free wires look awfull.
Both Wireworlds sound nice, both free wires sound nice...
Honestly, I never heard any significant improvement.
I use the Wireworlds practically for cosmetic reasons only.
A real pleasure when I am cleaning my room once a week: a split second I look at these beautiful wires, not seeing them again the rest of the time.
I am sorry, it is not my intention to start a cable debate, just wanted to share my opinion