Shimano's newer nexus coaster brake hubs are longer lasting and more tolerant of heat; being properly maintained of course....
I have the 3 speed version laced to a veep (it was given to me for free by a friend who finally went fixed) and living in a mountainous area, it proved to lose only a minuscule amount of stopping power with use although it would be hot to the touch. It's aluminum body and specialized lubrication (yes you have to buy its lube from shimano who has it specially for the nexus series; and you have use it every hundred miles) definitely helps.