acoustic zen reference or venustas

I agree this is a very subjective question. I have no experience with Acoustic Zen but comparing Purist to Nordost (which is the ultimate in detail and definition) to my ears its no contest. I would take a Purist cable any day over Nordost...if for no other reason than musicality and bass. You will never get more raw detail than with Nordost but, its how its presented that matters. To me their cables often sound analytical, forward, and thin in the bass. This is consistent through their line. I often hear people compare Purist to Cardas and while not always accurate, they share similar qualities. Cardas and Nordost are really on the opposite spectrum in approach, design, and sound. For me, I would recommend Cardas or Purist any day. None come cheap however.