Phelps = the best swimmer we will see in our lifetime. And he's not done.
I'm old enough to remember Spitz - who probably won his races by even bigger margins than Phelps (3 body lengths in his 200 fly). But the world of swimmng is vastly more competitive today and Phelps is world class in every stroke but breaststroke and distances between 100 and 400 meters. Even his breaststroke is VERY good, just not top 10-20 in the world. It was a joy to watch him race.