I'm pretty sure James' stance is do whatever sounds best to your ears.
I use a Shunyata Diamondback Platinum on my B60. I originally used a Venom. I tried out the Venom because I damaged the jacket of my OEM power cord. Not a lot, but chafed the jacket enough wher I felt it probably wasn't very safe. The Venom (and Diamondback Platinum) had a 100% money-back guarantee, so I figured why not?
I liked the Venom upgrade. At first it sounded a bit rolled off in the highs. After listening for a bit, I realized nothing was rolled off, the system just sounded more relaxed. Kind of like it was breathing easier. I'm not going to say there was more shimmer here, more bloom there, etc. That stuff sounds like a bunch of fluff BS. To my ears, everything sounded more natural and at ease.
2 years or so later, the Diamondback Platinum went on sale for 50% off with the same return policy, so I tried that out as well. I figured that if it was better/worth the cost, I'd move the Venom to the DAC. The Diamondback did everything the Venom did, but at a step higher. I then added the Venom to the DAC, and it sounded better yet.
I paid $125 for the Diamondback Platinum and $100 for the Venom. Both were pretty effective 'tweaks.' I'm sure not everyone will like them, but that's how everything goes in this hobby.
I honestly didn't think power cords would have made a difference at all. The Venom was bought as a might as well try it out thing when I needed a replacement anyway. Tyring it out paid off for me.