I rented an M10-R for a weekend and it was liberating, dare I say! Not only was it easy to carry around (no lugging a bag!) but it also REALLY drove into me the fundamentals of exposure, which is something I have admittedly neglected these past years.
Won't lie, I absolutely love my A1, 24-70, and 70-200 (both gm2s). AF tracking is insane, the quality from the sensor + optics are excellent (for me), and my keeper rate is great! But with that said, I feel I've lost the "fun" w/ shooting the last few years, and for some odd reason, the M was fun to play around with the short time I had it.Similarly, the prior Canons and Nikons I've had in the past didn't provoke me with that sort of "fun" either (well maybe the N6006 and my dad's old A-1, but that's when I really got into this hobby in Jr High ).
What also piqued my interest in rangefinders/Ms was seeing a handful during our Tokyo trip over the summer; I felt slightly uncomfortable (probably my overly self consciousness) to use my A1 to capture street pics/casuals, lol. I gather I wouldn't feel as intimidated (nor would live subjects) if the A1 wasn't as imposing.