Amsoil made a big deal of how good they made the new PI a couple of years ago. They have a money back guarantee till May 31 if you have not used it before.
I don't know how good it works since I have not tried it on a problem engine.
I doubt anything is any better. I would think the Techron and the redline are needing a reformulation by now. Though I am sure they are still a pretty decent product.