Setting my PS4 to limited or full makes absolutely no difference. Not sure if this is a good thing or a bad thing. I tested it by taking a screenshot in a dark area of Dragon Age Inquisition, then changing to limited, and taking another screenshot, then comparing them side by side. No difference at all.
My Bravia doesn't seem to have an option to change RGB output either... I went all through the various menus.
Strangely, my PS3 is set to Full, and there's a VERY noticeable difference if I change to limited- the XMB is completely washed out and looks awful. Changing it back to full makes it look normal again.
I've watched youtube videos, and read articles on why game consoles should never be set to full range RGB if connected to a TV, but these don't seem to be 100% correct for all types of displays.