I began photography in 1983 with a M2, then a M6. I lost them in the flood of Arles in 2003.
Since 4 years I was shooting nearly exclusively with my R-D1, but I bought a M43 camera for video and I began to take pictures with more and more often.
I think it's because I like the special result of the C-Mount lenses.
I would buy another digital RF camera to use my M lenses with, but M9 and even M8 are too expensive for me, and too dangerous to "wear" in the streets where I'm shooting …
I'm mostly an ultra wide lenses shooter (12 and 15mm) so I use mostly an external VF and hyperfocal settings.
Then, the most important for me it's not really the RF, but the sensor size, the IQ and ergonomy of the camera.
Sure, I like telemetric focusing too, when I shoot in low light conditions with fast lenses (e.g. Ultron 28/2 or Nokton 35/1.4) - but it's not so often.
So I'm watching for a new manufacturer system (Ricoh, Nikon, Fuji?) who certainly will offer me in few months/years to upgrade for a new not-so-expensive-M-mount camera with large sensor.