Again, being away from racing for a while, I didn't know about this. Great Andrew Beyer column from the Washington Post:
http://www.washingtonpost.com/wp-dyn/content/article/2006/10/18/AR2006101801725.html

On New Artificial Surface, the Difference Is Real

Racing fans from coast to coast have been observing the Keeneland meeting with intense interest. What is happening now in Lexington, Ky., may portend the future of the sport.

Keeneland replaced its traditional dirt track with a synthetic surface, Polytrack, heralding a revolution that could sweep the country. Turfway Park and Woodbine have also installed Polytrack, and all of California's thoroughbred tracks are converting to artificial surfaces, beginning with Hollywood Park next month....

When Keeneland opened, many jockeys were riding with some of the aggressiveness that they would display on a dirt track. But trying to get the early lead proved to be a bad strategy at the new Keeneland. Of the first 48 races run over Polytrack, only one horse managed to lead all the way -- and he was an odds-on favorite with vastly superior form. Many outstanding, high-class speed horses were unable to win....