CaptZoom
Established
Never used an OM-D, but I can't believe the GH3 has better ergonomics than an M9, I had a Lumix G1, and it was very confusing in IMHO.
I get the weather sealing thing though, I've missed shots because I was in heavy rain with camera I didn't want to get wet.
Not better ergonomics, rather good ergonomics. On the M9, my only complain is the location if the ISO button. It should be close to the shutter release, or at the very least some place where I can use it without having to take the camera away from my face. I will definitely upgrade my M9 to a new M when they include weather sealing (done with the new M), and relocation (or availability of a custom button) of the ISO to a readily accessible area.