I did a test render of two spheres with exactly the same texture. One was render with antialiasing normal and one with antialiasing draft. I could not see the difference between the two except that draft seem to antialias as it render ( no separate pass for antiallias) and it took almost 4 times longer to render. When I render to disk , at 300 dpi, I get a great resolution and detail. So, when would you use antialiasing draft??