Factory High Stall Converters

Have you ever driven a car with a modern 9.5" convertor in it from a place like dynamic or ultimate? You would be surprised as to how well they behave.
I had a Circle D converter in a late model Mustang. Cruising around town it felt stock but hit the gas pedal and it felt like you just added 50 horsepower. It dropped my ET half a second in the quarter mile.