Somewhat interesting, but irrelevent. It is wins that count. Clay- Nadal, Grass- Sampras- Hard- Federer. Overall, not just Slams: Roger, Pete, Agassi, Rafa.
How is Pete's ground game better than Agassi or Nadal?! Pete's serve was the most important part of his game. Agassi and Nadal are far better in rallies than Sampras - can't imagine Sampras living with Nadal while Agassi could.