I thought this stuff was a joke because of the name, then I thought it was just typical guitar forum hype juice, but when I actually tried it, I was shocked. I had a few guitars, not cheap ones either mind you, that would just barely hold tune, but not quite at a studio level. After putting this stuff into the nut slots and bridge slots, no more tuning issues. I apply some after every string change. The big applicator is a bit bulky, but will still fit most guitar cases and will last quite a long time (the small package lasted me for months).
Great stuff, should be in every guitarist's maintenance drawer.