Haven't used it, but mine is diesel. It's primarily a stabiliser which keeps the fuel in good condition (e.g. keeps the ethanol in 10% solution). But all top line fuel supplies have this in their mixes. I would definitely use it if I was running on E10 for the first time, especially on an older vehicle. There could be all sorts of material in the tank waiting to be dislodged, and possibly quite a lot of water at the bottom. As you know, ethanol is hygroscopic and will absorb small amounts of water. This can be beneficial actually as combustion will remove it permanently, but only up to a point. Too much water can saturate the fuel and cause the ethanol to separate, leaving you with a mix of two liquids. Ethanol/water solution at the bottom, and a reduced octane gasoline at the top. Not good for anything, especially starting in winter.
So I might buy it if I had an older car, for a couple of tanks or so. A member elsewhere has made the valid point that a hybrid car which doesn't use much gasoline needs to be aware that E10 will degrade over time through evaporation of the higher hydrocarbons (alcohols). In these circumstances a stabiliser might be worth trying.
I have never been a fan of additives but have started using a diesel cylinder STP type lubricant. This is because today's low sulphur fuels have lost the lubricating qualities of their predecessors.