I've a M240, which is a bit larger than the M10. I use the hot shoe often for the EVF and therefore the thumb support is not practical for my use. Furthermore, I've the handgrip too - it came with the camera - but I don't use it, because it makes the camera larger and heavier. To improve holding the camera, I put some anti slip tape on the notch and front of the M240. This gives me a firm and secure grip on the M240. Thanks for your review.
Interesting. I have also the thumb grip, but I hardly ever use it because I like to leave the hotshoe vacant for the Visoflex, that I use sometimes. You could then argue just to mount and re-mount the grip in accordance with the use of the visoflex - however, I'm worried that the excessive mount and remount of the thumb grip will wear the hotshoe to much, and sort of expand it so eventually it cannot hold the visoflex firmly in place. Have you any experience in that regard?