It is difficult to exactly copy anyones serve (especially pete's or edberg's).. but if you could, which of these 3 twist serve motions would you teach your pupil (or kids)? 1) Sampras 2) Rafter 3) Edberg I expect no one in their right mind would try to copy Edberg . But between Sampras and Rafter, I would go with Rafter. His margin for error was a lot higher than Sampras.. Granted Rafter's speed was 10-15 mph less, but it also spun more and kicked up more. Sampras had a much lower margin for error on his kick, but it worked for him because he practiced his serve so much. I doubt anyone else can work that low margin as effectively or accurately as Sampras did.