I am asking the same question with my M20s. I have been using McIntosh MA 6200 which sounds quite good. I also got at a good price an Accuphase E202 which is now at service being cleaned and made glorious. However I have heard that the Odyssey Stratos as an amplifier (I can use the Accuphase as a pre-amp) is great or even a Krell KAV-250a. I must confess to an unsupportable preference for older equipment(go AudiogoN). I was even told that the newer M22 doesn't sound as good as the M20 - the change was for a match to their newer floor series.
Integrated For Revel M20s
I just purchased a pair of Revel M20's on this site for a second system. Any recommendations on an integrated for them? I'm thinking possibly Plinius 9200 or Musical Fidelity 380, but have not ruled out lower powered options like Pathos Classis 1 mk2 or Unison Unico. Any feedback would be appreciated