I can see RBE only in certain circumstances.
One easy way for me to reproduce it was with the THX video optomizer test, I believe from the Nemo DVD. There are 2 tests that show circles in the center of the screen, for 4:3 and 16:9 geometery testing. They are gray circles on black backgrounds. If I look around the screen, I see the circle break into 3 closely spaced rings of red, green, and blue.
Other places I notice are on dark scenes with small light objects. In Harry Potter: Sorcerer's Stone, there is a scene in a dark room with a single bright candle. The RBE there was fairly pronounced, if I went looking for it.
Otherwise, it's definitely better than a color wheel based display. I don't consider the amount of RBE in the xx89S models a deal breaker.