Hydroboost braking systems

69383gts,
I have an 04 Mustang GT and my son has a 96 Saleen. They both have hydra-boost brakes and I can't feel the difference between hydra-boost and vacuum boost, until I shut the engine off.
My 340 Dart has the .508 cam in it and it can get a little touchy at an idle.
The Buick Grand Nationals also had the same set up.
I also put 188k miles in 2 years on a Ford Super-Duty 7.3 and never had an issue with them.