Børge Indergaard's honest, studied review of the Leica M Typ 240 is well worth a read. His main concerns are: white balance and skin tones.
In general, my experiences mirror Børge's, though when natural sunlight hits the sensor, I find the M240 nails both skin tone and white balance. For reference, read the following article: Nagano, Japan: through the Summicron 50.
When cloudy light, or mixed light gets in, problems can arise. I carry a WhiBal card in my wallet for use with all my cameras, especially when shooting indoor events. (Interestingly, the M240 shows less green cast than the Fujifilm X-T1 under fluorescent lights, which is why I prefer to carry it to headphone and camera shows.)
As to the eternal rangefinder conundrum, accurate focusing requires a perfectly calibrated rangefinder. Børge's M240 had to go back and forth to Leica's factory for adjustment. That's typical and has been typical of all rangefinder cameras.
Unique to Leica in the digital world are basic electronic lockups. Despite their long history as a camera maker, they are a German manufacturer of analogue cameras. True to most consumer goods, Japanese electronics are more reliable.
Anyway, good read. Thanks, Børge.