Orpingtons are very sweet and gentle birds. As far as human friendly I would say the pet/show breeds often are. They were bred for 200+ years for beauty, brains and friendliness/personality (vs egg laying).
My little bantams literally "purr" when they are held, you can feel them rumble/shiver from delight in response to the attention/affection. The hens also make great broody hens.