Based on your experience, then, would you conclude that the GH3 is the equivalent, IQ wise, of the OMD?
I'm not a camera reviewer and I've found cameras are very, very personal, even when judging file quality . . .
Given that I have shot thousands of images, video and stills from the gh3's and OMD's.
To me there not the same cameras regardless of format. They don't even feel or act like the same format.
The GH3 to me, is like a 5d whatever, just slightly smaller, with much better movies and autofocus.
It's a camera you can pick up, make a few menu selections, like type of still file and size, type of movie file and size and go shoot.
It also feels like a tool. I don't purposely try to abuse the gh3's but I'm not careful with them either. I mount them on cars, windows, booms, hand hold, just about everything you can do with a camera.
The evf is great, the wysiwyg viewfinder is great, the handling for a still camera (with the optional grip) great for stills, good for motion.
For motion, they suffer from the dslr type of package which makes smooth handling more difficult, but possible and makes things like the touch screen focus very good, but also more difficult when using one hand to shoot, one to mark focus (but once again doable).
The only downside in video is the bloody run/stop switch. You either use the recessed one which is hard to use, of set it up for the shutter switch which is easy but also very easy in video to touch it and stop recording. Since the info on the screen blinks out after a period (I assume there is another setting) you can shoot for 5 minutes, think you've recorded and you haven't. This isn't just me, everyone that uses the GH3's on my crew have that happen.
The OMD is more like a leica. Not exactly in the way it handles, but because it's more difficult and the buttons are very small, very sensitive. A few hours a day will take you a week to get all of your settings right and it has the most complicated, deep, crazy menu in the world, like 20 something settings and 85 layers and if you accidentally hit the wrong button (very easy to do) it goes back to no menu or the main menu and you start over again.
I rarely use the OMD for video because it shoots 60 fps though a nice 60fps, is tricky to set up and has no headphone jack or sound bars for video (a must).
The only thing it has for video that the gh3 doesn't have is great internal stabilization. If your good and smooth it looks like a bloody stedicam, (seriously). Nothing I've ever used comes close
The Gh3 also has a better lcd screen and evf. (not 100% better but better).
For still quality, I thought (and still do) think that the omd makes a sharper, more contrasty and detailed file.
The GH3 file looks like the video (which can be quite beautiful). The GH3 still file looks deeper, slightly richer and not as sharp, not as contrasty with smoother roll off but it also seems more non pretty noise where the OMD noise is nicer.
Both go to 800 iso in stills easily, the gh3 much higher in video, but if you know how to process both can go to 1200 without any real loss.
Note: Now one thing is if you put the OMD lenses on the GH3, instead of their constant 2.8 zooms I usually use, the GH3 looks more like the OMD because the OMD lenses are brutally sharp.
The thing is I also compared the two before buying. More than I've ever compared any cameras and really didn't need to buy the OMD, but wanted to. I love the build quality of it, love the way it looks and I love what I shoot with it.
Maybe it's nostalgia but it looks like a film camera, feels like one, until you get to the bloody 10 million menu settings.
The Gh3's just can't be discounted. If you want or do shoot video and don't have one, then your missing something. They are very, very good at video. If you want to shoot stills they're fine, actually very good, but you can get any smaller dslr and shoot stills and get as good a quality, maybe better, except they are the finest example of an evf I've used. Actually really, really good.
The OMD, is just different. I love what I shoot with it. I've finally learned it until it's intuitive (which like a leica takes time to make it feel like second nature), but it does now. I also love the 4:3 aspect ratio for verticals and unlike 35mm cameras do not shoot too tight. It focuses snap on, though doesn't track as well as the gh3, but it does hit focus really, really fast.
Once again, to me they are just very different cameras. If I had to throw one away it would be the OMD because the gh3's do so much, but I'd really hate not to have it.
Now, the only pixel peeping I've done is next to the canon 1dx. The 1dx is a great still camera, shoots everything fast and accurately and since I've had 8 1d series, it's second nature, but the difference between the files, at least in what I shoot is about 10%, if that, if you process really, really well. If you don't you'll think both 4/3's are behind, but if you learn how to move the sliders, they are very good.
One more thing. With the omd, I've done something I never thought I'd do which is to shoot it from the lcd. I do it all the time and I frame stills better that way (don't know why) but I see everything and love the framing.
Today did a set up horizontal and pulled the omd lcd out tilting up and shot it like a waist level camera. The results were nice and I tried to shoot the same angle with the 1dx and never could hit it.
Don't know why other than with the lcd I could view everything and the framing was perfect where with the 1dx like all 35mm cameras, I shoot too squeezed on the sides, but as I said, cameras are very personal.
I know this information doesn't help because neither one will win, (unless you shoot video) but they are both very electronic and do take some time to get use to them.
The OMD takes more thought, the gh3 is easier, the OMD feels better but with the gh3 everything is where it should be (except the video on/off), the gh3 has mic in and out, headphone in and out, a pc connection and well, everything.
The OMD has a goofy mic input (from the hotshoe) no headphone jack, no sound bars, no real video control (especially when shooting), uses prime lenses which are small and good but also takes me 5 primes to do what two gh3 2.8 lenses do, except go to faster f stops.
Now I don't really know about the next OMD, but I doubt if I'd buy it. If it had a new sensor, maybe, or better video . . . maybe but don't know why because the gh3's really have video covered.