I often read on camera forums that noise plagues the M4/3 cameras of all types at all ISOs. I guess its a matter though of how much noise bothers you or how easily it can be corrected in post processing.
But the real solution to noise is simply longer exposures. So the question perhaps should be are these cameras suitable for 30 seconds or less shots?
Otherwise you need to track them.
Same with most Canon and other brand APSc cameras. Very noisy but long enough exposures handles that.