I understand some people use DACs as a way to get different sound flavour. I used to be like that.
If comparing Cyan2 with iFi Pro iDSD with tubes, that is exactly what you are doing, looking for a DAC with a different flavour.
Cyan2 is beautifully transparent, in measurements and hence in listening.
Personally if I want to flavour my sound quality, I use DSP these days.
You definitely want high SINAD if doing DSP… I’m not talking single tone SINAD either but multitone…
if you start with low SINAD like Pro iDSD with tubes, then with DSP and digital headroom management, you might start hearing non-music things thanks to your DAC
There are very real practical reasons to have low noise and low distortion DACs and amps and speakers/headphones/IEMs, not just technical reasons on paper
Anyway no harm - I’m not here to tell people how to enjoy music. I just showed Cyan2 is transparent and the rest is up to the user 