I know there are varying opinions on the usefulness of ABS. Also, many think they can outbrake an ABS system on dry roads.
The Dec. 2010 Bike magazine has an interesting comparison of 5 bikes, 5 different riders (including their regular road testers) trying to stop their bikes with ABS on and off. This was done in dry conditions, warm pavement, standart tire pressures, stopping from 70 mph to zero.
4/5 riders thought they were stopping faster without ABS. None actually did.
I thought this an interesting comparison, especially since some of the riders were quite certain, before the test, that they'd be outbraking the ABS system.