I have A/B tested on my Metro Super Lead clone: LAR/MAR PPIMV, Faustine Attenuator, and the Aracom Attenuator.
The PPIMV sounded and performed the best to me. But it really depends on what you intend to do with it. A PPIMV will not sound that good at mouse-fart volumes. It excels at knocking the band-level volume of an amp down a few notches so your ears don't bleed. It's not really that good at playing at TV volumes. BUT, it is cheaper than a thousand-dollar attenuator. And to me, it actually sounded much better.
I have no experience with power scaling.