In our neck of the woods, we’ve had cloudy night skies recently (at least, since my E-M1II arrived).  So I’ve lacked a clear view of stars to test the beast on, but fortunately there are plenty of Christmas lights to work with.  Here’s a quick shot from one of the more-colorful nearby houses:

FWIW, I took this shot at ISO 6400, and hardly used any noise filtering in Lightroom (the rest of the pertinent EXIF data: 12-40mm f/2.8 Pro lens at 12mm, 1/15 sec, f/10, handheld).  Here’s a before & after (Lightroom) comparison of a dark part of the frame at 100% crop:

Looks pretty reasonable, if you ask me.