Been using Sea Foam since I heard about it on the iboats Forum site back in 2004. My engine at the time was a 90 Merc 2 stroker and in all that time I had the carbs off once and the problem was a piece of rubber fuel line, not ethanol varnish. I should have changed my fuel lines at 10 yrs and I didn't and yes I use E-10. Combustion chambers were squeaky clean. Kept it in every tank. Swear by it. Using that and Pennzoil semi-syn. TC-W3 you couldn't tell it was a 2 stroker except on the hole shot and there was barely a trace using premix 50-1 (I disabled my VRO at 10 yrs of engine age......just felt like it was time, no other reason.)
Was in a farm store today and the spray is now a different product than what they used to use which was just an aerosol SF they sold in a pint can. The new stuff has a lot more goodies on the label and the price attests to that....16 oz was 7 bucks for the non aerosol SF and 12 oz aerosol of the new spray was 10. They also now sell another version with a green label added to the regular red on the white can which is aimed at the penetrating oil market.