Never used or heard Nuforce in my own system, but i've had W4S STI-1000 fitted with high end fuses.
I used the STI in two systems, with sorted PC's and IC's.
I decided to try JRDG C-500 or W4S separates. I went for the C-500 which is way more expensive than the STI.
The C-500 is more refined and in a sense calmer in it's way of coming on. It is smoother but at the same time more detailed. It has better 3-d (depth). In direct A/B with STI-1000 (PS Audio high end fuses equipt), the STI sounded slighly forced, sharper and more pronounced in the top end. This affects the whole tonal spectrum.
I suspect the PFC-1 unit, inbuilt in the C-500 has alot to do with the results. Oh, PFC is a Power factor correction unit.
For tech spec, look at JRDG's info page.
The W4S is a good amp and i agree it offer much for the money.
However, changing powerchord(s) and/or platform etc, can not do what the C-500 do.
Even though, it helps. I would, if trying diffent fuses, try Furutech instead of PS Audio.
I expect, next step (upgrade) would be Vitus SS-101mk2 (;-) or darTZeel CTH-8550.
Or JRDG Corus + 625. These are completely other prices though:-(
I have heard from a friend, doing A/B of C-500 and Mcintosh MA7000. The MA7000 is quite good, but it can not match the 3-d and transparency of C-500.
Talking W4S amps, when is the Ref series expected to be released?