by Bill D.
I don't know about the Sharper Image Sweet Spot Finder. The picture you show is of the Check Go device that spins the ball so that it settles into its balance point at which time you insert a sharpie to mark its true equator. Perhaps I'm just a fool hacker, the second adjective certainly applies, but I started rolling my putts better with the balanced balls immediately and my drives are hitting more fairways as well. It's the best $25 I've spent on golf this year. I've noticed the tell tale equator line on many close up shots of putts televised in Tour events also, so I've got good company.
Bill D.

by Terry V
I started believing while watching long putts. If the ball is not struck correctly, the line takes off wobbling. Within ten feet, however, the line "straightens" itself out. The ball WANTS to rotate on that axis, so it only makes sense to start it there. Call me stupid, but you can't have my Check-Go!!