I'm not a fan of distance fields for GUI text rendering. Their main advantage in games is super-easy integration into the rendering pipeline (they're basically just a texture and a simple shader), but the quality is not quite as good as standard font rendering. There are other issues, including fairly large texture RAM requirements for CJK fonts, and no easy way to do do variable fonts. My main work these days is piet-gpu, which is intended to do 2D graphics (including font rendering) "the right way." In the meantime, using existing platform glyph rendering capabilities makes sense and will certainly give the best visual match to platform text.