Strange.. I've tried yanking the steering around at full braking on a variety of ABS-ed cars that they seem to steer ok and predictably.. although like you say, the ABS pulses are a bit distracting. Hmm... but they never really got in the way of steering...
Maybe you want to get someone else to try out your brakes or you try their car.. maybe there is something wrong with yours.
In any case, steel braided lines are a good idea.
