There is no substitute for hard work....most aspirations of life can only be fulfilled through hard work, ...but it is commonly seen that some people achieve similar heights with less hard work than others, this is where the element of smart work comes into play. If a person's efforts are channelized in a proper manner (in a smart manner), even lesser efforts can lead to greater outcome. Often smartness in thinking and working, is linked with creativity and lateral thinking. Using one's creativity or looking at things from an altogether new and different point of view often leads to the discovery of new shortcuts of doing a task, which saves much time and energy.
So, the point is that smart work is definitely better, but to be a smart worker one must have an attitude of doing hard work.