It is amazing that he can return serves when he is stretched wide off the court. 
That's so amazing; no wonder he is currently ranked as world no. 1 by the Association of Tennis Professionals.
He had won lots of Grandslam tennis. Australian Open is the most successful grandslam tournament for him since he won 10 times (I believe).
Yeah; I heard he now owns five Wimbledon titles including the 16 Grand Slam wins
I have no doubt that he will win at least few more. He is catching to Rafa and Roger for Grandslam titles. 
Isn't Federer better than Novak? 
I would say yes if we are in the decades of 2000s when Roger was able to win multiple Wimbledon, Australian Open and US Open. 
I agree; with the US opens not far away; Novak is closing in on Federers all time record for grand slam wins. Thats so interesting.
Since 2010s, Nole starts winning. He is considered the alpha of men's tennis. He is still proned to injury like many others. 
Novak is known as the searcher;  Roger the pleaser and Rafael the fighter off course. The 3 big men in Tennis
Roger is the matter of time whether he'll decide to retire soon or not. Rafa is usually good on clay turf. Nole still has winning potentials.