I've shot with the G1, G2, GH1, and GH2.
I have been surprised by the improved dynamic range of the GH2. I didn't expect that. The G1 and the G2 provided similar IQ obviously. The GH1 surprised me with its banding (grumble), but I got it on the way cheap as a stand in, so I shouldn't grumble too much.
I have no idea how the G3 sensor compares to the GH2 sensor in terms of DR and IQ.
If the OMG
has the G3 sensor in it, with the other features that are leaking out, it merits a look for me. The reasons to add it into the mix with my GH2 would be image stabilization, weather sealing, and shooting experience. If the ergonomics/setup/functionality makes the shooting experience more enjoyable, woo hoo
. It apparently has a tilt screen and a viewfinder which are also on my list.
Doug