In NGUI you can bake all kinds of effects to the font by selecting the bitmap font prefab and using the "Modify" section. Using the inspector setting is inefficient, as the label has to be rendered multiple times in order to achieve the desired effect. In case of shadow, it means it's drawn twice. In case of outline -- 5 times. Shadow + outline would be at least 6 times. If you bake the effect using the Modify section, the label will only need to be drawn once. Plus, you can do much nicer looking effects.
