LOL well without A7 I would not have got the M9, because it got me used to a bigger camera. And course M9 was benchmark to compare lens performance with---I have a decent RF selection I was using in backcountry with 5n.
I will use both A7 and M9, I think they are very good, complimentary pair. The A7r I found very impractical, since it is crazy picky with glass--but excellent with native stuff. I sent that one back.
A7 is totally different camera as far as images are concerned, and very lens friendly compared to R. But I love 18-21-28-35 FOVs and I came to conclusion M9 just rules in that range. Since I already had the glass, I just bit the bullet.
.......
What I learned today: when the shutter light is flashing, you forgot to take off lens cap, and framing 28mm is not easy with glasses.
anyway, I'm not in the league of most of the regular M9 shooters, obviously, but so far I love the camera.