For a start, I dont profess to know much if anything, but all cars I've driven (passenger, 4wd, sports) with ABS seem to 'let go' a little when the ABS kicks in. That is, they deccelerate slower when ABS is active.
I've always found the best technique for maximum braking is to rapidly but smoothly apply the brakes (to give the suspension time to load up and settle) until you get lockup on (hopefully) one of the front wheels, then to back it off slightly until the wheel unlocks then increase pressure again until you feel the edge of traction being reached again.
It sucks your eyes out of their sockets if you get it right in a car endowed with decent sized brakes.
I've always found ABS to be a little disconcerting when driving hard. What with the pedal shudder and the general sense that you're forfeiting a little bit of car control to a computer somewhere under the hood.
But thats just my 2 cents.