One of the stats that absolutely blows my mind about Federer is that, in addition to his winning his 20th major (an incredible statistic in its own right), he has made it to 30 major finals - THIRTY! Are you kidding me?
On top of that - do the math...Federer has won 2/3 of all the major finals he has ever appeared in - he has won twice as many major finals as he has lost! And it hasn't been during an era with weak competition either - Roddick, Nadal, Djokovic, Wawrinka, and Murray (among many others) have been in the way during his career. Winning half of your appearances in major finals would be an unbelievably good stat - I don't know if there is a word for winning 2/3, especially going to 30 in the process...
I thought, among many others, that Sampras' major mark would stand for decades - now there are two who have won more. Mind-boggling. IMHO, I agree - Federer has to be considered #1. This era of men's tennis has to be considered among the very best too.