Windslyce tracks and cars are Australian made and cost about 65 percent of the equivalent Harken or Ronstan system.
I have a Windslyce track and car on Top Gun and Harken track and car on Bullet, the Windslyce car runs smoother under load because it has twice as many balls.

Disadvantage of the Windslyce is the balls are not captive but that is easy to work around during removal.

Darryn