Power cords are funny. For me, they make a larger difference in the sound of my system than interconnects and speaker cables. Here is why the “last five feet” makes a difference beyond just the wire gauge matching your equipment needs. The area behind many of our systems is cluttered with cables, some power, some signal. The more cables, the worse the challenge for each cable to do its job, namely keep the signal as intact as possible and delivered from point A to point B, or deliver adequate current to power your gear without affecting the signal in the adjacent cables, and limiting digital hash from entering your power strip/conditioner and eventually affecting your other gear.
So your power cables have two jobs: 1. play nice with your power supplies, and 2. keep from “polluting” the environment where your other cables are carrying your signals generated in your precious and in many cases dearly priced electronics. How a power cable performs is completely system dependent, including whether you have a dedicated line, what kind of outlet you are using, do you have a power conditioner, what gear are you using, what is the configuration of your cable looms in the back and what specific cables are you using for analog and digital signals. Engineers spends countless hours attending to the layout of signal and power pathways in their gear. Whether you are aware of it or not, you are doing the same thing with the cables behind your gear, but likely with much less care.
I now assemble most of my own power cables from parts, but I am running one Shunyata and a “Black Shadow” cable which I like very much. I am partial to Japanese manufactured wire and connectors but I have been experimenting with some Chinese made products recently and I am finding some of them to be remarkably good for the money, but certainly not all.
The best advice I’ve seen here is to tell the folks at The Cable Co. what gear you have and what your budget is and ask for their recommendations for some cables to borrow below, at, and well above your budget, and then just listen to hell out them and see what you like and what works for you. Because what works will be system dependent the cheapest cable may sound best, or not. And if none sound better than your stock cables, then you send them all back and are only out the rental fee.