Okay, so I ran through a tank of gas with this stuff, and I think the engine has never run so smoothly the whole time I've owned it (for about the last 5k of the car's 37k miles).
Obviously, quantitative measurements are the only way to know for sure what it did for performance and what else it might have done to the engine. I'm not equipped for that.
Just to be on the safe side, I plan to stick to the manufacturer recommended product, in the future. I read somewhere it's Techron, but I'll be checking on that.