It depends upon your perspective. Since a mechanical mod uses no regulation methods, it is dependent upon the power straight from the battery. The battery will start out fully charged at 4.2 volts and then gradually decline until it no long can produce vapor around 3.4 volts. Vapor will never be as good as when the battery is first put in the mod, and will be gradually downhill from that point on.
A regulated mod uses a regulating processor chip which keeps the voltage steady from the beginning of the battery until it is depleted. This chip will drain a little more from the battery than a mechanical mod because of this regulation, but the vape quality will remain constant for the entire time the battery is in use. If you choose to use a higher voltage than 3.7 volts with a regulated mod, that higher voltage is naturally going to pull more amps from the battery to do so, so the battery won't last as long as in a mechanical mod whose voltage is at the mercy of the battery's voltage.