I have an issue with the assumption of the title...
I have played in a very popular Canadian Pro-Am event a few times. One of the years, the greens were so fast that the course became unplayable for all amateurs and most of the pros. Fastest does not equal best.
Best is when conditioning emphasizes the architecture.
Excessive speed will undermine great architecture.
Thank you Ian for that comment.
I lost my cool just reading the title.
In my opinion, the best greens I have ever played can NOT be defined by Fast or Smooth.