I have the XA-25. It is a superb unit, it does nothing except make the signal bigger!
To quote Stereophile "...what might be the most transparent amplifier available at any price". The review sums it up.
It is not sterile but do not expect quite the luscious midrange that 300Bs can yield.
I go back, forth and around rolling between the XA-25, a completely upgraded Elekit TU-8900 (including Lundahl OPTs, Jupiter Paper-Wax caps, NOS RCA 2A3 tubes, Amperex ECC82s) and a home brewed push pull, balanced 6SN7 (NOS RCA Black Plate), 300B (current production WE) and Lundahl OPTs. (I am 81 years old and can just move the XA-25, 63 years ago I was in the university crew and a bit of that has stayed with me)
The XA-25 is (probably) the most resolving and accurate, the Elekit allows me to listen inside the soundstage and the 300B is just seductive.
Perhaps, for what I have spent on those three amps I could have fond one that had all of the qualities - but I doubt it, as I suspect that the enhancement (?) by the tube amps precludes the ultimate resolution of the SS.
My speakers are Rockport Atria IIs (87dB @ 2.83V, 4 Ω) that I bought before the 50% price increase!