Originally Posted by Flash O'Groove
But if your strategy is to hold serve and win the tie-break, then you should rather go with Karlovic, Raonic, or any -ic serve. Because if you consider that to use properly a Federer forehand, you need to have his footwork and his shot selection, then you also need to have Sampras serve selection (and mental fortitude) to use it properly, as well as the game to back up this serve, which also was great to set-up points. With Karlovic's you don't really need shot selection. You just have to execute well, and if you do, even if Agassi or Djokovic know exactly where it will land, they can't do a lot about it.
Yea I haven't even watched any Sampras match so I would also take a Raonic/Karlovic serve. It's just that Sampras was mentioned in the OP and I wanted to make the point that it's better to have a great serve than a great forehand.