Well, I might say there is an outright answer to this question: it depends on various factors. Those from arthritis, for example, would appreciate electric winders because they use minimal hand operations.
Electric winders are great and efficient, however, they have their cons too. You need to be closer to the wall socket at all times when using them. In other words, they are not portable to travel with. Also, you do not get full control of the tension of your yarn when using electric models.
Manual winders, on the other hand, are portable. You have full control of yarn tension. You need no wall socket for them to operate. A simple hand operation can wind multiple yarn balls or cakes.
Sandwiched between the two options are battery-operated winders. You need to carry batteries around—perhaps consider additional batteries for in case the others get depleted.