Jeff Rowlands Amp and Dac vs. VAC amp and DAC

A lot will depend on how much money  one wants to spend. A used VAC Phi 200 is a wonderful amplifier and much less costly than the newer VAC IQ  amplifiers. It would be ideal to compare the Phi with the newer IQ amplifiers. The Phi could be as good sounding or verify close,who knows without listening?  Given the cost of these amplifiers traveling to actually hear  them would be helpful. 
Charles, 

From all the indications, real time bias dramatically improves SQ.  The owner running 200IQ in mono configurations had Phi 200s.  Bottom line is how much do you want to spend?

Exactly, how much to spend? Listening is inherently subjective,  jaw dropping experience for one is modest or subtle difference for another. 
Charles, 

Thank you all again. I will try to listen to the IQ gear this weekend and see how it compares both in price and sound with the Sigma and the Rowland. I am booked to listen on Saturday morning. Not with the Wilson's but with speakers at the shop. I will take Al's advice to heart and all of your inputs when listening. There is a lot to digest here and it has been amazingly useful. Instructive. Thoughtful. And informative. I can't thank you all enough for your time and wisdom. Will let you know how it goes if you are interested!!!!

Rinpoche,
I look forward to your amplifier  listening  impressions. It's clear to me that you have good ears and can choose what type of sound presentation you prefer. I am very glad you have this opportunity to hear these amplifier candidates. It should be much fun as well as informative.
Charles,