As one who is bruised and bloody from the GC wars, allow my $.02...

GC does not work with many characters "out of the box" because they were designed to FAKE Gamma Correction out of the box. All of the ambient tricks that are built into those shaders are FALSE and first have to be turned off/down/etc to get rid of the faking they are doing before they will look right using GC.

Most of us dweebs have no clue how to correct all these errors. BB tried to explain this to me countless times and the problem was, I never understood where the controls were to make the adjustments he was telling me would solve my problems. It was not until PP2012 that I found the python scripts that would do it for me! At that point, I became one of the leading proponants of GC... because I WAS FINALLY SETTING IT UP RIGHT!.

That said...

If you are considering GC in your workflow, then get EZSkin and SceneFixer... both free from Snarleygribley. http://snarlygribbly.org/3d/forum/ These pyton scripts will do all of the basic fiddling you need to deo with just about anything you're likely to use. I would not be without either script, GC, or IDL at this point.