The Zisc truly is the best frizbee for my chocolate lab Amber. She loves to retrieve anything, sticks, walnuts, rocks, but the Zisc is her favorite. She loves to bite the center and carry it back to me like a taco, perhaps that is why the center gave out on the first one. She loves to violently shake and spin it and after the center pulled out it finally ripped the outer ring and no longer flew. We bought the first one Sept 2007, and West Paw was quick to honor their one-time guarantee with a new one.
After several months, the new one is showing signs of love, a puncture and a slit in the center, but still provides hours of joy for Amber.
Unfortunately for me, I have been diagnosesd with frizbee elbow and have to be more careful about throwing sticks and frizbees, the Zisc is great because it goes farther than other frizbees which means more exercise with less throwing. (But i need to keep it off the barn roof)