Canon EOS-650D vs Olympus OM_D colors
and often comes down to what you are used to. Being a long time Oly shooter I do prefer the colour rendering from Olympus. The same may apply to someone who has shot Canon or Nikon for a long time. I've tried the NEX system and didn't care for the colour (too much Cyan bias for my taste) and also I found I'm not keen on the rendering from Panasonic cameras (White balance always seems more of an issue and often results in a magenta caste). I also liked Fuji's rendering of colour, which seemed very natural. That being said, these are just my subjective preferences and others may, and do, take a completely different view of it. There is no one manufacturer who does it "right", just right for me. I feel these differences often do come down to white balance fine tuning but I'm not interested in fiddling with UniWB, I just want the camera to get it right as much as possible, in this respect Olympus generally do a pretty good job, or make it easy for me to fine tune it (If I shoot jpeg).
I've also found that shooting raw does not totally eliminate colour differences. Even in raw different manufacturers still produce sensors with their own colour signature, or should I say via their image processing pipeline. The Olympus flavour of the Sony sensor is certainly different from Sony's output in the NEX line. I've also come to realise that colour rendering is more important to me than I originally thought and won't buy a camera that doesn't produce colours I'm not keen on. This was one of the reasons I have now totally committed to Olympus in m4/3's, they just produce colours that work for me, as always, YMMV.
Any problem on earth can be solved by a well aimed Pomegranate...