All of my experiences with ABS are in BMWs. I was on California Hwy 101 just north of the turn off in to Palo Alto when someone without ABS made a hard stop which immediately put him into my lane 90º to the direction of travel. I was, fortunately, in my wife's BMW 540i wagon. I went into the ABS hard and stopped about 1-2 feet short of the blocking car. Neither you nor I can stop faster, period. The nose on the car dived so hard, I was surprised it didn't hit the pavement.
Now, if the GM ABS is a poor performer, I'll look into some sort of cure for that, but for the most part, ABS works and I'd never replace it otherwise.
Of course, the choice is yours, your truck.