It's been discussed time and again. Skidding is not the most effective way to stop.
Wikipedia
"An anti-lock braking system (ABS) is a system on motor vehicles which prevents the wheels from locking while braking. The purpose of this is twofold: to allow the driver to maintain steering control under heavy braking and, in most situations, to shorten braking distances (by allowing the driver to hit the brake fully without the fear of skidding or loss of control). "
The same general principles apply for bikes.