The only person that even comes close to Federer is Nadal. Federer is just such a great all-around player. He can play on any surface and he has an all-court game. The way he can hit his forehand like a more classical eastern forehand or get some extreme rotation and hit like a western forehand is just amazing.
I must be sounding too much like a tennis player, so I'll stop there. Bottom line is that Federer is great

.