I just went and did some night photography with the M9, and I am very impressed with the results. These photos are not really the greatest (part of my ongoing series on the fish drying areas outside reykjavik), but I am very impressed with their technical qualities. I used ISO 160 at f/1.4 for between 30 seconds and 177 seconds. In the M8, I found that these long exposures were very noisy, even after the dark frame. On the M9, they seem to be nearly noise free. In fact, I have pushed them up to 3 stops in lightroom and they are still not particularly noisy. Even at f/1.4, the results are sharper than what I have been getting doing similar work with the D3. It still does not have the light gathering ability that the D3 has, but for shorter duration night photography it is pretty impressive -- it has retained nice color too.
By the way, I should note that this was taken in the middle of the night, with the only light being a mostly full moon -- that said, many of the photos were shaded from the moonlight by the hanging fish above. It was quite dark.
That was just 30 seconds, pushed 2 stops
That was a 60 second exposure, pushed 2 stops
125 second exposure pushed 3.25 stops (!)
177 second exposure pushed 2 stops and with 28 points of fill light.
These were all straight from lightroom 3 beta with the standard sharpening and noise reduction.
Here are two 100% crops...please note, these were taken at 1.4 (50/1.4 asph for the first, 35/1.4 asph for the second), and I had to focus with a flashlight...and the first file was pushed 2 stops, the second 2 stops plus a lot of fill light:
Anyway, I am sure it would look better with more exposure and a smaller aperture, but overall I am pretty impressed, especially since these are 18mp files that do not need to be shown at 100% even for quite large prints.
P.S. It was -9 degrees C (16F), so perhaps that helped keep the noise down as well. The M9 kept working perfectly for 2 hours battery was still at 65% (it started at 80%).