They're a typical German breed...hard-headed but not difficult to train, and they are a reasonably intelligent breed.
Griffs are NOT a German breed, they're Dutch. The best Griff couldn't compare to the worst Drathaar.
BULLSCHIDT!
The breeder was a Dutchman who developed the breed over a twenty year period in GERMANY! They were further developed as a breed in Germany, France and The Netherlands.
I've had Drats, also, and they were no better or worse than the Griffons.