I hear many Floyd nut huggers complaining about Manny's credible opponents. If we take away their two common opponents:

Oscar de la Hoya (Floyd - split decision win, Manny - Oscar quits on his stool)
Ricky Hatton (Floyd - KO12, Manny - KO2)

this is what we have:

Manny Pacquiao:
Miguel Cotto, TKO 12
Joshua Clottey, 12 round unanimous
Antonio Margarito, broke eye socket, 12 round unanimous
Shane Mosley, knocked him down, 12 round unanimous

Floyd Mayweather:
Big Show at Wrestlemania
Juan Manuel Marquez, Floyd comes in over the weight, 12 round unanimous
Dancing With The Stars
Shane Mosley, nearly knocked down, 12 round unanimous