Audioquest custom made triple weave design power cable (Storm Series).

I have tried braided geometries and they are much more beneficial when compared to a more standard cable geometries.

However, it gets more complicated as you delve further into the "science" of cables.

The best geometry I have tried/built is this Helix (i.e. spiral) geometry detailed on my web site...
http://image99.net/blog/files/category-002ahelix-power-cable.html

It provides a very "black" background together with a very dynamic presentation with a well controlled and deeper bottom end.

Feedback from people that have tried them has been extremely positive - reports indicate they are beneficial regardless of the "quality" of the component they are attached to, but lower-end components will show a significant improvements e.g. are my own componetns...
- NAIM amp - improvements were subtle, but more refined - e.g. venue acoustics more evident and focussed
- Simmaudio Moon LP5.3RC phono state - improved top end clarity and precise image, improved attack
- Blusesound Node 2 - significant improvements across the board, i.e. dynamics, clarity, image, bass control

I use a 10 gauge version for amps and distribution and a 13 gauge version for components, but I am now thinking about a lighter 16 gauge version for digital components

Unfortunately this cable is a DIY solution and is yet to be produced commercially.

FYI: Anticables and Lessloss have both been producing braided cables for a few years and they have some very nice options

Other cables I believe would offer better perfformance than braided PC’s come from Nordost (expensive) and KLE Innovations (more resonably priced)

https://kleinnovations.com/kle-innovations-klei-products/klei-ac-power-cable/

http://www.nordost.com/power-cords.php

Hope that helps - Steve

RE: 

Garth Powell is on record (see below) that the braided design is not for sound quality, but only to make the cable flexible

Pehaps that is the case in his design - however ...
- if you take a 12 gauge extension cable from home depot
-  remove the outer sleeve i.e. extract the conductors
- braid the conductors togther and attach IEC/mains plugs

The braided cable will actually outperfrom Furutech 10 gauge bulk cables that have just had Connectors installed at each end
- improved image, bass depth and dynamic performance

I have observed significant improvements on my system using braided PC's - but the HELIX design is by far the best.

A friend just went through the Home Depot braiding exercise on his guitar amp and reported significant improvements over his stock cables.

I also use a braided power cable on my bass amp
- HUGE IMPROVEMENT!
- deeper bass with much more control

Regards - Steve

Guess that makes me and about 15 others quite delusional :-)

The following amps I and others have tried good power cords on the following amps - they showed discenible improvements in sound quality...
NAIM
Ayre
Gryphon
Audio Research
Cambridge Audio
Marantz
Bluesound
Bel Canto

On the guitar side of the fence her are three I have tried
Fender
Marshall
Ampeg

Or perhaps they are just poorly designed?

I guess this debate will go on at infinitum - just sayin :-)

Regards - Steve