I've never had them. When I was a boy in 4-H someone showed a pair at the county fair. That rooster was the meanest, nastiest chicken I had ever seen up to that point in my life. I resolved to never keep them.
I ended up with a silkie rooster that was even meaner, so it probably less the breed than the upbringing.
Those Spitzhauben roos would stalk children that came to the farm and attack from behind. Never had any other breed do that when running feral. These guys sought out ways to get themselves on the "no fly list".