This is only slightly less controversial than an oil thread.
Here’s my take: When ethanol replaced whatever poison they used to put in gasoline to help emissions, many of the rubber/plastics used in fuel systems weren’t compatible. I’m in the process of replacing all that stuff in my 61 Evinrude.
In the years since, that has mostly changed, so if you’ve got a recent build, it doesn’t really matter. But…
Besides my infrequently driven Spyder, my Ducati sits almost all the time (103 miles last summer. And that was a 3 year high). It used to take the better part of an afternoon to get it running in the spring. Since I started using eFree gas 3-4 years ago, I charge the battery, open the petcock, pump the throttle 3 times, and it starts the 4-5 time.
Same with the Spyder. It sits a month or two and generally fires right up.
On top of that, all my vehicles require premium. In my market, eFree is generally 4/5¢ +/- the premium price. And the Porsche, Smart, and Mercedes all get 3-4 mpg better mileage with eFree.
If eFree is readily available in your area like it is here, I say go for it.