That is good advice Bill K.
I owned the M300s for several years and sold them last year. I currently own the Atsah NC1200 monos and a very tricked out McCormack/SMc DNA-2 LAE. So, I have had Class A, Class D and very good Class A/B amps all within a year. They are all very close in power ratings and not far separated in price. I still can't decide whether to keep the Class D monos or the Class A/B amp.
If I still owned the M300s the only thing that would change is that I wouldn't be able to decide between three amps, instead of between two amps. All of these are excellent sounding amplifiers, near the top of their class, and I suspect I would be happy with any of them but, they do sound different from each other. Listening with your own speakers is a really good idea to be sure of what you are getting.