Testing out a NanoFlash external recorder with the GH2, I was surprised to see just how different the color is between the onboard recording and the external recorder. The GH2's monitor output is pretty much useless for evaluation if the camera isn't recording; when paused it's outputting a totally inaccurate signal, and once you go into record mode it starts outputting a more representative signal, but even then the color saturation levels are way off. They're much lower in the monitor or external recorder than they are in the camera-native footage.
In this video I overlaid the Nano footage over the camera-original, and then sliced out 1/2-second increments, so that you'll see 1/2-second of Nano, and then 1/2-second of camera-original, repeated over and over.
Best way to view this would be to put it on "repeat play" or download the original file and play it in Windows Media Player or Quicktime and put the "repeat" flag on, and you'll see the color saturation pumping dramatically every 1/2-second.