I got my first M, an M6, about 6 months ago. I had been lusting after one for a while, but could not justify the cost. So I bought a Canonet QL17 III to deal with my rangefinder craving..
3 months later I still wanted the M6 as much as before so I bought one. It was meant to be my last camera, but it had the reverse effect, it made me love rangefinders. Since then I have bought an Olympus XA and last week I got a Contax T.
I can imagine that selling an M would always be a mistake. I love using the other cameras, but when I pick up the M6 it makes all the others feel like cheap plastic.