...Musical Fidelity M3 amplifiers and they were not as satisfying. I am using a Rogue Sphinx now in a secondary system...and it is pretty good...
I have AV8 Wave amps, Prima Luna integrated, Quicksilver monos, six packs, M3si, and a Parasound A21. I just ordered a Sphinx because I needed a little tube sound but not the heat or wear of power tubes. Replacing my M3si. Good to hear it might be an upgrade.
I think the OP is on the right track for heat reduction, I'd pick my A21 for his system.