If you have touching faces rendered using different shaders, different lighting/material properties and/or different textures, internal edges rendered using subpixel antialiasing will look bad, which is why FSAA using multisampling is the preferred way to antialias on any system that has sufficient fillrate.
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If you have touching faces rendered using different shaders, different lighting/material properties and/or different textures, internal edges rendered using subpixel antialiasing will look bad, which is why FSAA using multisampling is the preferred way to antialias on any system that has sufficient fillrate.