Muscovy CAN be extremely sociable and very good companions, however, they can also be the worst duck around because of their large size, their talon-like claws, and very hard, bony 'knuckles' on the wings. If they're prone to flogging, this would be like getting hit with a big stick. Drakes raised with too much human contact can cause a lot of problems once they reach sexual maturity because they are quite prone to attacks in their quest to be the 'top dog' (this is the situation I was referring to with the 'prone to flogging', as a general rule, in my experience, Muscovy are not mean nor aggressive unless raised as pets). There is a happy medium, you just have to be aware of the potential for problems and act accordingly. Knowing how to handle them is crucial or they can be difficult to deal with which can have a lasting impression on people and turn them off of Muscovy forever.
I have a clutch of 13 ducklings now that meet me at the gate every time I come home and chatter at me and I do not pick them up and pet them or cart them around as a general rule. That's just their natural social attitude coming through.