I tried my circular polarizer the first time this past weekend at a kids soccer game. It did great, the sky was nice. But I'm not sure if it helped with the black shorts as they seemed to have lost some definition. I should have taken some shots without it for comparison. The sun wasn't at a 45 degree angle either as it was 1pm up above and back from the camera.
I ended up getting a B+W - nice filter I got at a great price. It was pretty neat when I was testing it .. just turning it in circles to see what it does.