Interesting statistical analysis of every Grand Slam tournament in the Open Era which finds that the current era is statistically the strongest and best - followed by Aus Open 1990 with Lendl, Wilander and Edberg and then US Open 1981 with Borg, McEnroe, Connors. Even if people might not agree with the conclusions the analysis is really interesting.
The figures at the end about each player's peak at the Slams i.e. their best run over a 4 year period is staggering in showing how far ahead of the field Fed was - he got a "perfection" rating of nearly 80% - Nadal comes second at 58%, then Borg, Lendl and Sampras tied at 57% and so on...
There's also analysis of the rivalries - looking at the "level" both players were at when they met and what the combined "perfection rating" was. Fed/Nadal had the highest peak at Aus Open 09 final, followed by Djokovic/Nadal at Aus Open 12 final... A lot of interesting stuff in the article and worth a read. When 27 of 28 slams have been won by 3 players it probably doesn't need this much analysis to say it's the strongest top 3 tennis has seen at the same time but good to compare.... Rafole's achievements as ever are enhanced by the era in which they did it in - Fed's in a league of his own but it has to be said that if we only look at his achievements post-Rafa coming on the scene i.e. from when he had a top tier rival, 2005 onwards, then the gap reduces slightly - 12 slams for Fed, 10 for Rafa, 5 for Novak.