For me, it's Lomachenko. Won three world titles (in three weight divisions) faster than anyone else in history. Plus in only 14 wins, he has already beaten Gary Russell jr, Linares, Martinez, Pedraza, Walters and Rigondeaux and he totally dominates top class opponents, without hardly taking a punch. Lastly, surely he has the best amateur record in history, and it will probably never be surpassed. I know the amateurs are different, but I mentioned it, just to help emphasize, just how good he surely is as a boxer.