Hi Sam and Bill,
Concerning M625 and M725... The two devices show much more than a vague family resemblance. The most obvious difference is the sheer ability of M725 to drive my Vienna Muzik speakers with an authority and ease that I found to be extremely satisfying, and that by the way edges out that of the nominally more powerful 500W M312 stereo amp. Conversely, M625 may be more at home with slightly smaller speakers, like the Vienna Kiss that Roy Gregory has used in his review of the amp. Both M625 and M725 easily exceed the harmonic density and subtlety of my beloved old M312. But, as the M725 monos use ceramic boards and a few other technical solutions that have not been applied to M625 (4-pole capacitors?), they seem to be even more nuance and transparent than the already excellent M625 stereo.
as I already mentioned, the M925 are extremely promising this far, but with only 97 ours of full power operations, and about 35 hours on additional break-in of input transformers while on standby, they are apparently far from giving their best performance. Yet, factoring in some of the usual break-in anomalies, M925 yield a vast stage, solidity of image and profound authority that is new to my system.... They seem to be an ideal synthesis of all that limitless silky power that I remember being so fond on the old classic Rowlands like the Model 7 monoblocks, which I owned for over 10 years, combined with a new and very special musical resolution, purity, and total effortlessness that I simply never heard before.
Can M925 justify the price difference with M725: well, that is really a subjective thing, but.... This far, I suspect that they might.
PM me if you like to chat directly.
Guido