[Arragonis]

This is an interesting read.

The basic ingredient is the same in most of these additives: 50 weight engine oil with standard additives. The magic ingredient in Slick 50, Liquid Ring, Matrix, QM1 and T-Plus from K-Mart is Polytetrafluoroethylene. Don't try to pronounce it: call it PTFE. But don't call it Teflon, which is what it is, because that is a registered trademark. Dupont, who invented Teflon, claims that "Teflon is not useful as an ingredient in oil additives or oils used for internal combustion engines." But what do they know? They haven't seen the secret studies done by Petrolon (Slick 50).

and

In defense of Slick 50, tests done on a Chevy 6 cylinder engine by the University of Utah Engineering Experiment Station found that after treatment with the PTFE additive the test engine's friction was reduced by 13.1 percent, the output horsepower increased from 5.3 percent to 8.1 percent, and fuel economy improved as well. Unfortunately, the same tests concluded that "There was a pressure drop across the oil filter resulting from possible clogging of small passageways." Oil analysis showed that iron contamination doubled after the treatment, indicating that engine wear increased (Rau).

I think you pays your money and takes your choice really. Most modern decent oils contain all the additives required and being synthetic or partly synthetic do not break down as quickly or as fully as they used to.