Hey Rick. I've used Startron for about two years now. Don't use it in every tank but do on a very regular basis. My son was having problems getting his truck to pass EPA test and the mechanic told him about Startron.
I did a 20 fill up eval (10 without and 10 with) and found the increased gas mileage just about offset the cost of the Startron. I note a bit more pep with the additive in. I understand there is some octane booster in there.
Here is West Texas we don't have to worry about moisture much but the E10 gas is not the best for our bikes so if we can counter that at a reasonable cost then I'm all for it...