I have one and used it for a short time. In all fairness, my bow may not have been tuned perfectly, but I had a tough time getting the fletching to pass through the slots properly. The result was that I had fletching damage AND damage to the Whisper Disk's foam.

And, it may have been only me being paranoid, but it seemed like the arrows didn't slide across the foam well. It seemed like there was too much friction between the foam and the arrows, which slowed them down. I couldn't quit thinking of the foam on the disk being similar to a lot of the foam targets.