I have had one Ousteleti. Man they get huge!
I would say the Panther's I've had have been consistently chill and easy to handle. The one Ousteleti I've had was less chill and a little more intimidating (especially with their size!) but results will vary.
As others have said, it's primarily their individual personality to be chill matched with their keeper's daily handling that get's a Cham to accept you as just "another tree"...