The biggest difference between a Xiphophorus maculatus and a Variatus platy is that one is a real species of fish and the other is a hybrid that has been created in an aquarium. I tend to stay away from things like platies and instead go for the real wild type fish. I really love all of my species tanks of goodeids, my Xiphophorus montezumae, the Heterandria formosa, the Xiphophorus helleri and the rest of my single species wild livebearer tanks. I sometimes give in and buy a decorative molly or platy but they are for decorating a community tank, not for a serious wild type fish breeder.