The thing about ABS is this: It can pump the brakes at one wheel at a time (front wheels each in the case of 240s, and the rear axle as one). You can never do that with your feet.

Tests always show that stopping distance is decreased in all conditions except in deep sand or loose gravel where it is actually beneficial to have the material pile up in front of the tires for maximum stop. On dry, wet, or icy pavement or other hard surfaces, ABS always stops faster and lets you steer while braking, as opposed to steering/braking seperately, as one has to do on non-ABS cars when the wheels lock.