Rich,
Believe it or not but for pure fast, at the top level, I never saw a horse as consistently fast as Dr.Fager.Saw his last start at Aqueduct, 7f with 139 pounds, fight off a rival, half in 43.4, and cruise home in 1.20.1.
Keeping the subjective out, like best or greatest, he was the fastest horse that ever lived any era,imo.
Mike