Watching some highlights of Raonic match today, I have to say I think his serve is best on tour today. He really hits the spots and hits tons of aces/service winners. On fast surface like Madrid he's unbreakable
But in another thread, someone argued that Isner has, in fact, better serve. What do you think? I think Raonic is the greatest server on ATP tour right now. It's scary to think about the monster he'll become with more consistent ground game and better footwork.
I have also included a couple of other options, but I think those players are not as good as they were before.