Bigger sensors are as rule of thumb better for the stills, but it doesn't mean micro4/3 are bad....small camera is in numerous situations big advantage, just small sensor will always remain prone to diffraction due to its physical limitation. Many lenses don't reach their top performance before their diaphragm is stopped down: but micro4/3 sensors suffer only 2-3 steps down before the diffraction impacts the image quality, while APS-C or FF sensors perform well 5-6 steps, or as far as the lens performs well.

Choice of lenses you already own is important before the decision. Otherwise just google about all cameras that seem interesting for your needs and consider if you can use the lenses you already own....

What about Nex 7? Smaller than GHx bodies and top performer for the stills....

Get GH3 and get Pentax K-01 (if you are not needing VF, or K-50 if you need one) :-)

@acuriousman, if you're just a casual users like I am or even a pro the GH3 is really good. It's way better than the GH2 for still. Those two are not in the same league when it comes to stills. I was planning to buy a GH3 for video then pentax k-5 for still. But after seeing and playing the GH3 raw stills, I told myself, I don't need the k-5 cuz the GH3 meets all my needs. One of my favorite lens on the the GH3 for still is the lumix PZ 45-175mm f4-5.6. The added fact that I can control my GH3 with my smart phone and take pictures and upload straight too makes it even better.