I bought some last year via the internet direct from the States. Although cheaper than obtainable from UK, the 32oz bottle arrived leaking and 2/3rds full. A loose cap and flimsy packaging contributed.
As to it's claims - next question. I am very sceptical. There maybe, just maybe some bactericidal effect on the fuel, however as to improved performance- no sign of it so far.
No, despite the claims of, I believe Belfast University, I have found no benefits whatsoever.
So my advice- save your money- unless of course, somebody else knows different.
If it is a bacteriaside or fungiside its base may be similar to products used in aviation fuel which are ether/alchol based. They kill the bugs by raising the osmotic pressure and hence the little blighters get fat and explode. This is why dead bugs plug filters. If these products are ether/alcohol based then they will slighly change the fuel flamability and burn characteristics but the change will be miniscule compared to what might be claimed.
Bugs can only exist in fuel if there is a water bottom, the bugs live in the water and eat the carbon out of the hydrocarbon fuel.
Best advice is to remove tank water bottoms- but in boats that is not easy, on hot summer days tanks breath in the humid air as fule is consumed and at night as it gets cold moisture condenses and drips into the fuel in the summer this is a daily repetative cycle.