Originally Posted by Gustavo Kuerten
Let's compare the opponents they both had to play in Slam finals during their peak:
Serena: Venus (7x), Hingis, Davenport, Henin and Sharapova (2x)
Federer: Philippoussis, Roddick (3x), Hewitt, 35 yo Agassi, Gonzalez, Baghdatis
and pre-peak Nadal (4x)
Serena > Federer
You've forgotten Djokovic, Murray, Soderling and Safin.
Also Azarenka, Radwanska, Zvonareva, Safina, and Jankovic.