Congrats to Roger- without a doubt the GOAT
Being a half-decade older than Nadal (so that Nadal was in his prime longer during the rivalry) and Nadal being absolutely transcendent on clay (while merely being great on other surfaces), are two factors that we always need to factor into the head-to-head difference.
Just look at the times they've been in the Finals or Semi-Finals of Grand Slams:
Federer
Australian: 5-1 in Finals, 7 other semis
Roland Garros: 1-4 in Finals, 2 other semis
Wimbledon: 7-3 in Finals, 1 other semi
US Open: 5-2 in Finals, 2 other semis
Rafa
Australian: 1-3 in Finals, 1 other semi
Roland Garros: 9-0 in Finals, no other semis
Wimbledon: 2-3 in Finals, no other semis
US Open: 2-1 in Finals, 2 other semis
You obviously can't take clay away from a player, but:
Australian: 4-o in Finals, 2 other semis
Wimbledon: 1-1 in Finals, 3 other semis
US Open: 2-3 in Finals, 4 other semis
In Grand Slams, he looks like Andre Agassi off clay, and like no one else who has ever played on clay. And the first part isn't a slight, to be clear: Agassi was freaking great.
That makes him probably the second best player ever, but the ability of Federer to be fantastic on all surfaces, against all competition, makes him the GOAT in my mind.
Djokovic may pass Nadal (though if he's healthy he'll get another win or two at Roland Garros at least), though I think it will be hard for him to catch Fed: at least six more to tie? Federer is probably the 3rd or 4th best player still if he's healthy, and there may be other tournaments this year or next where Murray and Djokovic are eliminated without playing him. Not unreasonable to imagine Fed might get another.