M9 White Balance
The only complaint I have so far is that the (auto or incandescent) white balance for indoor images is TERRIBLE
Everything has a sickly yellow / green tinge
I know I can correct this in Lightroom (or other app)
With the M9, WB presets are a better starting points than auto if you are going to fix wb in LR. Sunny preset is the best starting point in my experience.
Tungsten (2900 K°) and sodium (2000 K°) lights are more difficult to deal with prests, so it's best to set manual wb: even a white car is fine for that, or carry a credit card sized wb card (any 12% or 18% is fine).
The beauty of shooting under mixed lighting with the M9 is that the camera does not try to even out the different light sources (like all my Nikons do) but records all individual light colors according to the baseline color temperature selected (you may or may not like that; I like it most since gives a strong personality to night color photos).