I'll never forget the first front disc brake car in the family. Uncle Charlie's 62 Bonneville. A panic stop tried through everyone through the windshield.
That is for example of every brand having faults in their early disc brake systems.
Uncle Charlies Bonneville sounds a lot like the only new GM truck my Dad ever bought for his business, a 1970 GMC 3/4 Ton. If I remember right it hydroboost brakes on it. Everybody that ever drove that thing complained about the brakes. I think if it were not for the gutter machine and rolls of gutter coil in the bed the thing would have stood on the front bumper.
I have not had an A-body with power brakes, ever. But the pedal does not seem right.....