This is something you really need to test for yourself. Every camera will react differently to under/over exposure, and the variable of exposing with a hardware light meter vs histogram vs internal meter vs zebras vs false color will make a big difference.
If you can, setup several scenes in the typical environments you will be shooting in; low light, back light, cloudy etc.; (It is probably best to have a person in the shot as skin tones are the most important thing to monitor.) Using the metering system and picture profiles you will normally use, expose your camera in 1/3 stop increments from 3 stops under to 3 stops over. In post grade these clips to normal and look through them all side by side. Also test different white balances, ISOs etc.; doing this you will learn a lot about your camera.
I have been testing the GH4 and G85 in this way in many different environments and with several different picture profiles for quite some time. I test, then use in in the real world, then test again. After hundreds of videos filmed all around the world in some of the harshest of filming environments, I feel like I have really hit the sweet spot with these cameras.
This is a quick project we just released yesterday shot with the GH4 and G85. Filming and editing was done in two days; shot entirely in natural light run and gun.
