How would you compare Acoustic Zen to Nordost

Acoustic Zen Silver reference is more punchy and boomy than Quattrofil.
Quatttrofil is more refined and smooth sounding.

Depends on your need. If you want something more exciting than maybe AZ is better choice.

However, there are still many cables out there.

I have compared AZ Silver and Matrix with Red Dawn and SPM, not the better Quattro fil. There is definitely a "house" sound to both ranges, so I feel able to comment. In fact my intro to Nordost was through one of the famous dems by Lars from Nordost at a UK Hi-Fi show. Very impressive it was to. It also gave a good impression of the changes between each level of performance. It was clear to me and others in the show, that the biggest jump was Red Dawn to SPM, but all had the same overall feel, lightning fast, but I find rather flat and tonally bleached. AZ, in comparison is richer, you might say coloured, but I find it makes music sound more musical, if that is'nt a tautology. There is a richer palete of tones, instruments and voices are more complex and interesting. It just sounds better dammit

WELL SAID! I agree completely.

I wouldn't use the Quattro Fil because it's not well-suited for fast digital sources. It's better for line level and phono signals. (That's why it's the one cable Nordost makes with a 5-pin din connection on one end to connect it to tonearm wiring.)
Why not use it? While most cables Nordost makes are fast like the SPM and propagate a signal at 99% the speed of light, the Quattro Fil lags behind at only 95%. Unsurprisingly, given its slower speed, its capacitance is 50% more than the SPM: 12.0pF/ft vs 8.2pF/ft. You don't want a cable designed that way for your intended use.
Acoustic Zen's Silver Reference mkII, on the other hand, is a good match for a digital source. It's fast, very musical, and highly detailed, especially in the upper mids through the high treble. For your application, given you have a mild hearing loss in the top octaves, it's perfect. You will never hear "too much" detail in the top and confuse that with coloration, IMHO.

Quattro Fil is old tech compared with Nordost's new Valkyrie (sp?) cable in the same price range.