I tried and owned HiDiamond P4, Shunyata Alpha Digital, Alpha HC, Sigma HC, High Fidelity CT-1, etc. None trounces others with the way you're suggesting here - night and day differences and the inferior one is trash material. Each have their own strengths and weaknesses and depending on the component you put them on, the characteristics may differ as well. At this price point for the cables mentioned above - higher than entry level by a couple of folds but may be a step or two below reference level - they are all good performers in their own right. Some maybe better than others on more parameters but it rarely comes without a weakness, at least IME. I prefer CT-1 over Sigma HC in my main system, but on my second system, even Alpha HC or Hidiamond P4 brings out equal level of satisfaction that I get with CT-1. It is almost always about system synergy and power cables are one of the hardest to do comparison in this hobby and for you to discredit a lot of cables manufacturers like the way you do is very disrespectful and TBH not really doing yourself a good favor either (although I do agree that there are as many shrill cable manufacturers as there are genuine ones).
NOTE: I did try Grover power cables, ICs and speaker cables a long time ago (cannot remember the model), I felt they were good for the price, but I had moved on from them for a reason I do not remember. If given a chance, I'd like to try the latest. But I'm not like you. As much as I know cables are important, I am a believer (also IME) in that once you address your system to a certain level of cabling, spending more on component change still gives bigger performance leap than spending more on cables.