Should I have an electrician hookup the electric mechanical exhaust fan instead of letting the roof co. do it?

I have to have my roof replaced. Two roofing companies so far have included in the estimates that I need ventilation in my attic. The air conditioning service man at my work said 1) do not let them put in a whirlie bird, rather put in an electric mechanical exhaust and 2) not to let the roofing company hook it up -- let them make the hole for it and put it in, but call an electrician to hook it up? Do you experts agree?