What make AO better is that there court speed is medium making every player and their style countable. Players are fresh also.
For me Wimbledon is little bit better than all three because of its history but putting US open over AO is stretch seeing how well AO is organized.
For me others three are equal in value.
I would value all four equally because the best players in the world all show up for each of them and try like hell to win them.
I think Wimbledon still has a bit of an edge on a resume, but that may change as time goes on. The AO used to be the weak slam because it was so hard to travel there. There were years when Australians dominated it. Think of the two wins by Rosewall late in his 30s. There were great players missing.
But now I think it is a lot like the USO used to be. It was sort of the "upstart" and got more and more prestige when Americans started to dominate. When guys like Connors were battling to win the USO every year, and later JMac, it was hard to argue against the USO when #1 players in the world were American. This goes back to people like Kramer, Gonzales, so many others.
At that time many Australians were the greatest in the world, so the only reason the AO was not the best slam was that it was so hard to travel there.
The rep of a slam depends on who is dominant. When a guy like Vilas wins RG, people tend to say, "Well, why not? The guy is a dirt-bagger. He can't win much except on that surface."
But when Borg came along and won 5 Wimbledons in a row, people started to pay attention when he won at RG. The same thing was true of Evert. She won RG 7 times. People would have said, "So what? She was useless off clay."
But with 7 wins at the USO, 3 at Wimbledon, and even 2 at the AO (in a time when most people did not even go there), her wins at RG stick out like Borg's. Same thing with Nadal. He single-handedly made RG almost made that the most important slam for awhile. Fed tried to win it for years, and Novak hasn't done it yet.
By the way, what is the biggest prize in 2017?
The AO.
Why?
Because now people are wondering if an wen someone else besides Novak will win it!