Color will vary slightly from camera to camera and scene to scene, especially depending what you have your saturation ratings at and such. Even professionals have a tough time with color at time. If you really want to nail color, you could carry and expo disc, shove it on your lens before shooting in a scene, run a quick custom white balance and you're good to go until you change scenes/lighting/etc... Basically your camera is trying to figure out in your scene what 18% gray is, and if it cant figure it out, it will do it's best guess. Even us professionals carry gray cards with us, or expodiscs, or gray discs, whatever that we could shove in front of the camera before shooting a series of shots. If you're more of an auto color guy, you can keep it on AWB and pray it works well or try to best match your scene such as cloudy, flash, tungsten, etc... Also making sure you nail exposure could depend on color fidelity, richness, and consistency.