I have to echo Tvad's post. He pretty much nailed my impressions of these power cords.
I might add, I do like the fluid Dominus in some applications better than Ferrox. Mostly on Digital. Also, the fluid did work very well on my turntable motor controller. All other areas (preamps, amps) I liked the Ferrox. But I am running all tube amps and pre's. Solid state or a different system may yield a different result.
The Purist 20th Anniversary, yields a improvement over the Dominus. Blacker back ground (much), better details, seems to blend the mids of fluid, the extremes of Ferrox, all perferctly. It's just a amazing cord. Sounds like live music in a killer venue - like the Myerson in Dallas.
Personally, you can't go wrong here. They do get better the more you spend.
Good luck !