I just bought a Opus power cord (for my amp). I had it on demo for a few weeks. I'm impressed to. I would not say it's all around better than my previous cord. But is clearly a better match for my system and ears in the area's of dynamics, beauty, textures in the bass and top end. The Transparent Opus power cord is very similar to the Opus signal cabling. I could see someone saying the Transparent Opus Power cord is dark in a comparison...but it presents all of the information just in a more natural and pleasing way to me. It's one of those things that you keep comparing and you just keep going back to it...goes for the heart vs the head.
It is not perhaps related to topic but I am impressed with Stage III power cords. Perhaps similar to Transparent Opus PC, they first sound as dark, but then one realizes that they even contain more high frequency detail but there is no hi freq noise, distortion just the data. Kraken is a significant step above any power cord that I tried, Leviathan is a better Kraken almost in every way.