which is best m4/3 body? .. Oly bodies or Lumix? overall.. size, weight, IQ, design, performance etc ..
If you want scientific results, there is lots of information around. That's fine; lots of people buy cameras based on scientific results and are very proud of their possessions.
But maybe your goal is not scientific perfection, but rather to take good photographs. I'm going to kick off a firestorm here, of course, but IMHO taking consistently good photos requires an eye-level viewfinder, backed up by an articulated LCD. Why?
1) The shooting position using an eye-level finder is hugely more stable than a shooting position where the camera is held out in front of the photographer, waving in the breeze. Say what you like about image stabilization, what it does is to mitigate (not eliminate) the effects of an unstable camera hold. Not that I don't use it, but my goal is always to have a stable hold in the first place.
2) The eye-level finder is usable in bright light situations where the LCD is completely overcome and useless.
3) An articulated LCD, subject to being able to see it in bright light, is useful for very low angle shots that would otherwise have you lying on your belly (see example below; it has not been cropped) and for overhead shots that you simply couldn't otherwise get.
Continuing now to kick up the firestorm, IMHO the major advantage of using the LCD is that bad composition and not-tight-enough framing are much more obvious on the LCD than they are using an eye-level finder. But people have been taking well-composed and tight photos with eye-level finders at least since Oskar Barnack invented the 35mm camera, so it is hardly an insurmountable obstacle.
In a studio situation using strobes or a tripod, the disadvantages of a fixed-LCD-only camera are almost non-issues. But that is not the environment most of us work in.
So ... I happen to favor the Panny G1-type design because it gives me what I want. But I have never played with the add-on EVFs available for other bodies. If you can get the combination of an add-on EVF and an articulated LCD in another model, then I would suggest that it also be on your short list.
OK, I am now going to dig my old Nomex out of the closet!