http://www.grc.com/sr/testimonials.htm
Originally - I had collected on his 30 day money back guarantee after learning that additional hardware would be needed for 48bit LBA disks. But things happen....and two months later I quietly sent him a "restoration fee" to return my license
I use this product on every disk we buy before placing them into service, and consider Spinrite to be a standard troubleshooting tool for ReplayTV units.
Have been told that some free utilities provide equivalent performance ...