I had a similar experience after receiving new M224 amps last year. The physical size and cool-ish operating temp were something I wanted, though. I was looking for a small format mono design that could "disappear" behind my speakers and I wanted a cool running piece that did not heat up the room in the warmer months. These amps were the best conventional A/B alternative to Class D models that I was also investigating.
I have been involved in music playback for a long time and still conditioned to think more-is-better in terms of power amps. So, yes, the M225s were something of a different direction altogether in terms of heft and quantity of materials. But these M225 are exemplary performers. Plus (and a big plus), I so do not miss moving around 50, 60 or 70 pounds of power amplifier.
We have a design that is locked into a balanced output. There is plenty of gain coming out of this differential configuration. There is no need to add circuitry to cover both single-ended and balanced output. There is no auto-on, or power-on trigger circuits, etc. The regulated supplies add some design overhead but does not require unnecessarily high voltage ratings on the rails and keeps the voltage steady. So, the power supply does not have to be anchor heavy to accommodate voltage sags and swells.
Also, I have come to understand that the output bias in a good design has an optimum range where higher is not necessarily better. I am now thinking about how efficient these DVA models are and I did not have to transition (yet) to Class D.
