I work for a man who was in the petroleum industry several years ago. back then, All the brands had their gas mixed in specific places. I/E. Exxon, Bp, Shell, et al made their mix at their big tanks after it came through the pipeline; then to the trucks to deliver to stations. But now, not so much. A truck is loaded with fuel. Then the additives are put in on the spot. Then it delivers a run of whatever brand is mixed. Same truck willl take a load of another brand tomorrow. Not sure I'd believe that there is more than a tiny difference in most brands. We do work for some oil companies that run several brands - Sunoco, BP, Marathon, Exxon. They work together to be able to buy bulk fuel so their prices stay reasonable. Some single store sites may have a difference, but then, the owner make take extra pains to make sure his gas is clean, filtered, etc. Or maybe it's all horse poop. most of the lower grades are not that different from brand to brand. THe Premium fuels have more additives to keep engines cleaner. The article referenced has some debate in the comments section over this point.
The article does not state what grade of fuel was used in the test in the web article. Just that you should spend the money on "top tier" fuels. Is this even in 87 grade? Or just the premium with VPower or Invigorate or Whatever each brand calls theirs. My gas cap says Ford recommends BP gas. I bet it ain't cause Ford researched it and decided that brand was best. I bet some money wexchanged hands for that little BP logo (helios it's called) on each gas cap. BP probably footed the bill for the gas caps and more. But that's fine by me. there is BP near me that is competitve with every other station plus carries ethanol free for my bike and lawnmower.
More the problem with ethanol blends is the effects is has on the fuel system. I worked for the state motorcycle training program as equipment manager and got to see first hand how bad ethanol blends are on carbs and such. In as short as a week, ethanol can start separating from the gas. If you own a small engine - weedeater up to motorcycle, either use ethanol free or drain the device when not in use for more than a week.
How was the test conducted? 100 hours of idling is not same as 100 hours of high speed running. Again, I saw this in the motorcycle program job. Our bikes would be worn out in 3000 miles. Or less or more. depending on the maintenance at th e individual sites. But a class is let's say 12 hours of motorcycle running, no more than 25 mph. lots of time sitting in line at idle. That's a lot of hours but not a lot of miles. I've seen all kinds of stuff in the engines, valves, plugs, carbs, etc.
Just my thoughts...