I have both on the F-450 in my sig, a Wolverine stick-on on the pan, and the factory block heater. The Wolverine allows me to run any grade oil I want in winter (currently straight 30) without worrying about whether the engine will start & starve for oil in temps below 0F., and the block heater helps the top end & heater warm up faster. I've even stashed my old 6A battery charger underhood & used a cube tap to power all 3 at once. Although, last winter, didn't even need it.