I didn't expect such a dramatic improvement in image quality. I was planning to apply some mods to my SNES to improve image quality (such as replacing a voltage regulator, adding capacitors, stuff like that). With this cable all of the mods are unnecessary: image quality is amazing. Not only sharpness and colors have improved, but even notorious vertical bars which are visible on dark screen, have completely disappeared.
Just to be clear, I'm using SNES with RetroScaler 2x, which by itself is improving image quality. But when I'm changing a composite cable to the S-Video cable, the difference is stunning.