Is Roger Federer best male tennis player of all time?

Yes. He's won more major "Grandslam" (16) tournaments than any other male player to include a career grandslam and he hold's the record for most consecutive weeks (237) ranked number one in the world. Those two stats alone should make him the greatest of all time (at least as of now)! Of course, he has many other records and arguments that could be used to justify his GOAT status over other contenders: Pete Sampras, Rod Laver, Bjorn Borg, Jimmy Conners, John McEnroe, Andre Agassi, Ivan Lendl, Pancho Gonzales and current rival Rafael Nadal (all of whom GOAT status could be argued and reasoned in some way or another).