Tun, don't look at it as mechanical versus boxes. Instead, look at it as mechanical versus regulated mods. Mechanicals are simply devices that have a battery and contacts to deliver power to your atomizer. It will deliver whatever the battery has in it starting at the maximum when the battery is fully charged and fading as the battery charge depletes. Regulated mods "process" the power so you can set the power level where you like it and it will deliver the same power every time you press the fire button. there are additional features of a regulated mod but this is the condensed version. Also, both mechanical and regulated mods come in all kinds of shapes and sizes. Box mods can be either mechanical or regulated.
Does this help?