Dear Tanmay, No doubt Rafa is a very very special player.He's the only one capable of posing some sort of threat to Federer.He's got amazing perseverance.Every single point has to be earned in the hard way against him.HIs energy on court,his 'never-say-die'attitude are exemplary.But watching Roger on court is such a refreshing expierence,which no one else can match.Nadal's game is at times boring and predictable.The difference basically is that of a great artist and a great carpenter.If you consider the tennis court to be a canavas,then Federer is the greatest painter who have graced the same.