Leonard with good reason. By the time he was 25, Leonard had fought Roberto Durán twice, Tommy Hearns and Wilfried Benítez. Later he won titles from welterweight to light-heavyweight and, for good measure, beat* Marvin Hagler in a fight for the ages. Pacquiao is amazing. Leonard was unbelievable.
It's a hard one because their careers don't really look very similar now. Leonard had such an amazing run in the space of two years with such a high level of competition (Benitez, Duran, Hearns) that it looks better than a lot of really great fighters' CVs. Pacquiao's two-year peak between late 2007 and late 2009 was just as awesome in its way, even if the level of competition wasn't as high. While Leonard has that remarkable comeback win against Hagler between his multiple retirements, his work is so fragmented that it's hard to compare with Pacquiao who hasn't stopped fighting in those 25 years and now has nearly double the fights that Leonard had.
Leonard beat the best boxers he faced, Pacquaio didn't. At least not without the help of bought and paid for cheating judges
