Some very reasonable comments. I think some confusion has arisen from the fact that some of the comments advocating the use of GC  have, as others have stated, come across rather as absolutes - with the implication that if you're not using it, you images are clearly, inevitably, metaphysically doomed to inferiority. I don't think anyone is pushing a hidden SM agenda, whatever their affiliations, but rather expressing their honest opinions. It's certainly refreshing to read some discussion of the pros and cons and when GC may or may not be the most appropriate technique. So, while the ecumenical spirit lasts:

1. In Vue, Kerkythea and some orher renderers, GC is implemented as a post-render effect. Is there an advantage to GC in the render process as opposed to post-render?

2. I rendered a scene in program x specifically designed to show the value of GC. I did two renders, one with and one without GC. Applying GC 2.2 to the non-GC image in an image editor, I can see no difference between it and the render GC version. Am I missing something or is there no difference? 

3. I often render in Vue using HDRI lighting. Does the use HDRI effect the need for GC in any way or is it still a case by case issue?

4. There still seems to be some suggestion that at least for certain scenes, GC is a must, or at least greatly preferred. What non-GC techniques can be used to mitigate for its absence?

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken