Mayweather deserves to be in the top whether no.1 or 2. Pacquiao also deserves either one of those. They have very different styles and in different competitive divisions. But the only difference is Pacquiao fights the best. While Mayweather is fighting the best in his next fight. So there will be endless talks on whos the best until both fighters fight their next opponent. Also it depends on how they defeats their opponents. They both win convingcly. Pacquiao knocks his opponents out. Mayweather wins lop sided decisons. Its hard to tell untill their done.