Part 3 gives the answer of why the Erwin Puts review seems so contrary to others: he uses lower levels of light that require longer shutter speeds at lower ISO. The difference is in the noise characteristics of CMOS and CCD sensors. Is the test fair? In low-light situations where you need High-ISO, there is not going to be a lot of contrast. Having the 14-bit images lends itself to a lot of post-processing to reduce Gaussian noise. The 12-bit Pattern noise of the M246 will require some careful thought with regard to fill-lighting. You don't shoot High-ISO in good light.
CMOS sensors have the analog to digital converters integrated into the chip; CCD sensors require an off-chip analog-to-digital conversion. This "system" noise is most likely less on the CMOS sensor than the CCD, and is a constant per image for a given ISO.
"Dark Current" is the noise produced within the pixel itself, and is a function of "integration time"- and temperature of the sensor. CMOS sensors have higher Dark Current than CCD's; some of this is abated by double-sampling on the CMOS during the exposure and averaging the signal. CCD's cannot do this; they do not have a "universal reset, sample,hold". For long exposure time: I suspect the Dark Signal in the M246 is the dominant source of noise, and is greater than that of the CCD. The M246 shows "Pattern Noise" at high-ISO. I suspect this has to do with the wiring-layer of the CMOS chip being in close proximity to the light-sensitive layer. CMOSIS has to "thin" the layer in between the wiring of the chip and the light sensitive layer below it. The geometry of the M-Mount is the culprit. Back-Side Illuminated sensors place the light-sensitive layer before the wiring layer. This type of sensor is more difficult to produce, but Samsung has an APS-C sized BSI sensor out in their camera. Put two of these together, like the sensor in the M Monohcrom, DONE. I hope Leica does that for the next generation. Best of both worlds for imaging and processing. At this point, make no mistake: CCD's are better for imaging with the M-Mount compared with front-lit CMOS. If you have an M240 and an M9: turn off lens detection on a fast lens and use on both. The amount of vignetting without applying a software correction gives the answer as to which technology is best suited for the geometry of an M-Mount camera. I've seen 1 person do this test, there was a noticeable difference.
The 14-bit M Monochrom will do much better in low-contrast light than will the M246 with it's 12-bit images. It takes a 10x relative change in intensity for the M246 to resolve points of an object compared with the M Monochrom.
What's all this mean? Well for one, it shows that there is a difference between CMOS and CCD imaging technologies. Knowing the relative strengths and weaknesses of each will enable the best from each camera. Pretending that there are no differences will leave you wondering why Erwin Puts is sticking with his M8.2. I know exactly why, I will never sell my perfect CCD array that has zero-defects M8. And I plan on keeping my M Monochrom and M9. also the DCS200ir. It's 22 years old this year. Still works. Has a first-generation CCD, made before microlenses were introduced.