Both help a lot when you are sensitive to direct bright lights. Without f.lux the colors were so piercingly bright, that I sometimes felt glared when I went awa

Both help a lot when you are sensitive to direct bright lights. Without f.lux the colors were so piercingly bright, that I sometimes felt glared when I went away from my Mac. Now, because it fits my lighting, the light brightness or intensity don't seem to change (as much). I really recommend using either one, especially when your eyes are sensitive.