Pass Labs AMP’s- What is the best Pass Amp Sound for You from past 10 years

So I have an XA-25 and its outstanding. I’ve tested the XA60.8 mono’s and there was not enough difference to move to them; no jaw dropping moments. Don’t get me wrong they were fantastic, but so is the XA25. Looking at the 350.8 or 250.8, etc.... even in comparison the Integrated INT-250... If you love it; want to explain what you like and why? I’m wondering what others are thinking... 
My set up: Wilson Sophia II’s, XA-25, Pass Labs XP-22 pre, Merging+NADAC.