I use an electronic caller because, the animal's focus is on the caller instead of the shooter. When the object is to kill as many animals as possible, I always prefer a combination of hand calls and electronics. Start with the hand call, and get them moving in your direction, and switch to the electronics so that when they show up, they are looking toward the sound, and don't notice when you bring the gun up. Hand calling all day or all night is extremely tiring, and it is my belief that they both receive about equal response. So, as a welcome relief at night, and because of a change of strategy, it's okay to use electronics, and in a reversal, it is absolutely essential that the animal be looking right at you, as the source of the sound. I would further posulate that it is not necessary to choose one over the other. Take both the machine, and an ammo box full of hand calls, and use them both, they work very well, together, or separately.
Good hunting. LB