:People have been doing Eotvos experiments with non-similar masses for a very long time now, pretty much right from the start, in order to test this concept. They've even done it with anti-matter because some supersymmety threories suggested antimatter would fall slower. In every peer-reviewed case I have heard of, the equivalence principle remained perfect to measurable capabilities. That page has a link to several such experiments, with modern ones that are to parts in the trillions. The P10 effect is parts per ten billion. These experiments directly contradict this guy's claim, over 30 years ago.