Michael's NEX-7 vs M9 comparison is badly screwed up, invalid, and thus, entirely pointless.
I do appreciate the effort, and I do agree that the latest generation of Micro-4/3rds and APS-C-format mirrorless cameras are a serious competition for the M8 and M9 cameras when used with M lenses. Actually, I believe Leica must, and will, develop some kind of "NEX-7 look-alike with 35-mm-format sensor and M mount" pretty soon.
However this partcular comparison is not worth the electrons required to transmit them. It would be better to take it down from this site because it's not only invalid but highly misleading. Michael's word has some weight in the world of today's photography, and he should not put his reputation at risk with such a nonsense.
Michael wrote, "I cropped the M9 images to the same field of view as the NEX. [...] I then resized the NEX files from 24 MP down to 18 MP so that they matched in both field of view and resolution."
After cropping the M9 files, to match not only the field-of-view but also the resolution, the NEX files must be downsized from 24 MP to 7.8 MP, not to 18 MP.
However, this is not the worst thing about this comparison yet. Even worse than this hard-to-believe arithmetical error is the fact that the M9 shots are out of focus. Hey! How can you dare to compare test shots when one set is properly focused and the other is not?
For the six shots (three with NEX-7 at f/1.4, f/2.8, and f/5.6, and three with M9 at the same set of apertures), the same lens was used from the same shooting distance. So any differences in sharpness at the same aperture can only come from the different sensors, right? However, in the NEX shots, the sharpness at the frame's center improves only marginally when stopping down; in the M9 shots the sharpness improves significantly when stopping down. How can the sensor affect the lens' response to being stopped down? Simple—it cannot. Instead, the M9 was slightly out of focus, and at f/2.8, increasing depth-of-field compensated partly; at f/5.6, almost fully.
Of course, it is to be expected that in NEX-7's higher resolution will lead to more detail in the final image, even after downsizing to the same pixel count. But the difference is by far not as great as the M9 comparison shot at f/1.4 suggests. Moreover, when Michael really was interested in image quality rather than pixel peeping then he would shoot his test with equivalent lenses (i. e. 35 mm on NEX and 50 mm on M9, for example) and then resize both full frames, without any cropping, to the same final size for presentation, be it digital files or prints. This way, you'd assess actual, real-world image quality rather than academic per-pixel quality (or here: per-sensor-area quality), and the M9's larger sensor area would be able to compensate, to a degree, for the lower pixel count. Throwing away the M9's biggest advantage over the NEX-7 is not a good start to arrive at a valid (from a photographer's point of view) comparison.
So if this screwed-up comparison teaches us anything then it's this: The opto-mechanical rangefinder is outdated by now. It cannot provide the precision that is required to reliably exploit the full potential of modern lenses on modern sensors. Accurate focusing with a manual-focus lens is much easier to achieve with the NEX-7 than with the M9. I believe the next Leica M will include some sort of electronic focus confirmation. The days of the traditional rangefinder are over.