Upload & Sell: Off
sangdabom, I also think there's a difference (I also own the 5DII with ZE lenses).
However, I think the difference mostly comes from the lenses. The Zeiss ZE lenses on FF are special. Colors, contrast, microcontrast, bokeh,... The m4/3 lenses are very good, but not at the same level IMHO. When I still used Canon lenses on my 5DII results also looked more flat.
BTW: I found the look of the RX100 files closer to my canon set. That sensor is even smaller than m4/3, but has a Zeiss lens in front of it.
I decided not to care too much about the rendering, because for me the OM-D is about speed, size and joy to use.