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. 
I have an X250.8 with Sophia 2's. I'm very happy with the combination. Very natural, organic mids and highs, and excellent bottom end extension and weight. Slam is very good (but not a Krell). Outstanding, realistic 3D imaging. I think the Pass brings out what the Sophia's do well without exaggerating anything or making them fatiguing.

Upstream it's an ARC Ref CD8 into an ARC Ref 5SE. The Pass works really will with that. Very happy with all of it. 
Has anyone compared X250.8/X350.8 to the X260.8 monos?
Will be used with Maggie 3.7’s.

How much better is the XP22 compared to XP12?
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I took an X350 home one weekend in 2002 for an audition. 19 years later- this past February I switched to the new X260.8 monos. My son has the X350 now. I’m using these amps with an ARC Ref 5SE and Thiel CS6 speakers and Purist Audio cables throughout. I can play it loud for me and the needles don’t move. I was nervous that I might feel the loss of the few watts difference from the X350 but no. It took some time for them to break in. Every time I listen now the sound stage is startlingly clear and focused. The highs are crisp and fast. That’s the best way I can describe it.