Happy New Year to you sir! My dad and uncle have used it on and off for a long time too. My uncle swears his boat needs a UCL with the lousy ethanol gas. He gets better power adding either MMO or TCW3 to the gas. He thinks MMO cleans better, but for a tired engine TCW3 gets two thumbs up from him. He feels it makes for a better ring seal which could explain the bit more power he gets out of the old 250 I6 powered boat he has, and a smoother idle.
Not everything has to be spelled out on paper with a labs letterhead to work. Many successful products were born by accident. Even with supposed testing companies screw up then have to issue TSB's and redesign certain products because they fail in actual use. So where was the testing done? In actual use in some instances. So I take lab reports, testing, studies, corporate data, related to the oil industry the same way I see an advertisement. As paid for BS.