I just got my personal Black Friday gift (ok, one of many, but still)- a One.3 at $50 off. I got both the 130w psu and the new battery. I used to own a Sensation M901 but that died on me. I also have a standalone Dodd Tube Buffer but after testing it seems that that now doesn't work either. Frankly I don't miss it too much. I remember the sound of the M901 to be better (cleaner, tighter, more dynamic) without the Tube Buffer. But the Tubes add some nice Tube warmth. Gone now, but ah well, that's life.
Anyway, I'm one of a rare breed here in that I use this only for my extremely inefficient Headphones- the Hifiman HE6. Upon plugging it in, the first thing that hit me was the refined sound. It's extremely smooth. This was what I loved about the Sensation, so glad it's still there. Will post more impressions as I listen in over the next few days, and with comparisons to my previous amp, the Temple Audio Batam Gold. Will also be switching out the PSU and the Battery to see what the differences are. Again, only with Headphones so YMMV.