Pretty crappy photos due to using my sons P&S and a complete lack of time but it gives you a pretty good idea. Essentially with both wearing grips they are nearly the same size, and for me fit in the same bags. In fact the hot shoes are almost the exact same height, but the body of the GH3 is taller. The main size difference is the depth of the body and that is also the key to a better hand hold (for me anyway). All in all I say the "huge size" of the GH3 is a bit of a optical illusion. Yes it is bigger but it looks bigger than it really is. Mainly because the body is taller (less of a difference between the surface of the dials and hotshoe) and deeper, but neither of those things actually take up space in a bag. Now if you don't use a grip on the OM-D there is obviously a much greater difference. Colored the GH3 so it shows up better. The GH3 is slightly wider although it doesn't show in the picture. This shows the slight extra width of the GH3 and its great total depth due partly to the viewfinder extension. [/url] With OM-D's flash mounted Oops look whos taller now (partial grip on OM-D, no grip on GH3) Notice that although the OM-D's hotshoe is taller, the GH3's main body is taller.