Updated 8/3/2012 for new firmware revisions.  Recently I reviewed the Sony BDP-S590 Blu-ray player and found that while YCbCr output was bit-perfect, with both 4:2:2 and 4:4:4 colorspaces, the RGB output had a flaw that needed to be addressed.  The BDP-S790 Blu-ray player arrived here the other day and I tested and confirmed that it has this same issue as well.  Because of this, I’m going to assume this affects all Sony Blu-ray players for the 2012 model year.

Update 7/30/2012: Sony has fixed the RGB issue in the BDP-S590 with a recent firmware update.  The BDP-S790 is expecting an update soon.

Update 8/3/2012: The BDP-S790 is now updated and fixed as well.

What this means is that if you select RGB, you will lose green highlights, your red and blue shades will be too dim, and your grayscale will have a green tint as it is pushing green while cutting the other colors.  The YCbCr output seems to be perfect for all practical purposes, at least in Standard picture mode, and is what you should use.  What does this mean that you should do?

• Use YCbCr 4:2:2 or 4:4:4 for your HDMI Colorspace
• Do not use Auto or RGB mode for those

Sony has told me they will fix it on the BDP-S590 and I put in a request for comment on the BDP-S790 but I imagine it is the same.  Even if your equipment handles RGB better than YCbCr, the RGB mode has such a flaw you are better off using YCbCr in this case.