I think we need to classify these additives into different arbitrary groups.
First, the snake oils: This is stuff thats <$5 and available at your local auto zone. One that comes to mind is the GUNK engine cleanse. This is just pure diesel. You can smell it. It's just a pint of diesel to act as a solvent in your motor! So, unfortunately, MMO/marvel mystery old is part of this at $3.99. I use a bottle of it on every oil change, but do I KNOW it does something? No.
Second, the major industrial products: I reference the Kano/Kreen in this group. I ran this stuff as recommended in the oil and in the gas, and I didn't notice much change. Now, this isn't necessarily a problem with the product, I think I had just used enough other stuff prior to it, that it didnt have much to do.
Third, thickeners: Lookin at you lucas. This stuff fills the gaps, increases oil pressure (i guess) and does it really do anything for the longevity of a motor???
Anyhow I made a thread up here and posted what I've done thus far on my noisy burb:
https://www.tahoeyukonforum.com/threads/engine-noise-progress-with-videos.110089/
In short, I ran a quart of ATF for a few thousand miles, and it cleared things up quite nicely. I did MMO and the Kreen AFTER that period.......so had I done that FIRST, would my results have varied?? Not sure. I think Kreen is a bonafide product...I wish I had done that first, but I was expecting instant gratification from the ATF (because I'm clueless) and so I ordered the kreen while that was in the crank.
