Einstein is gonna make a clean sweep in this contest. While Newton is a great scientist, who to some extent paved a way for upcoming and inspiring scientists of his era, Einstein's theory of relativity and its wide range of applications in space and atomic science is truly unbeliavable and will continue to be useful for many more years to come. Newton's decoded simple laws of nature with reasonably easy mathematics formulation which was a breakthrough of its kind of his period and truly an inspiration for following scientists. Einstein, arguably the genius scientist of all era, on the other hand came from nowhere and formulated an amazing relation between time, mass and velocity whose practicability seemed intricated at that period but eventually proven to be true experimentally. So in my view its gonna be Einstein all the way.