In my experience, they both fail but differently. Electric winders tend to experience motor failure leaving you with a stuck window. They don't stress the mech

In my experience, they both fail but differently. Electric winders tend to experience motor failure leaving you with a stuck window. They don't stress the mechanism that much. Manual winders, you would generally experience mechanical failure. If you were lucky, you broke the handle. If you were unlucky, you broke the gears and had the pleasure of watching your window fall into the door.