I'm sure it has had an effect, but for most people, it's likely to get lost in the "noise". I don't think I've ever had exactly the same mileage out of two tankfuls, even when running the same stuff!
However, I have a 30+ year old petrol car, which is not suitable for E5 - never mind E10! I ran it on E5, and replaced all the rubber fuel lines, but E10 was always going to be a bit more of a challenge. When the time came, I started using Super Unleaded. It doesn't do many miles, so it has probably only got through about 3 tankfuls since I startd doing that.
I always fill to the brim and keep accurate records of brim-to-brim consumption. I can't say I have noticed ANY difference in performance or economy, going from E5 to Super Unleaded, but 3 tankfuls is nowhere near enough to form a valid opinion.
What has happened, though, is that the car developed a bit of a misfire / hesitation. No. 2 plug was black, wet and sooty, compared to the others. Compression test was fine. Oil consumption (difficult to say after so few miles) doesn't seem to have changed, and it doesn't smoke any more than it ever did. In the end, I took the injectors out and tested them. No. 2 had a bad spray pattern.
Whilst it's only a theory at present, I'm wondering whether, after 30-odd years on E5, these extra "clean-your-engine" additives in the Super Unleaded fuels are starting to dislodge deposits and that's what has knackered my injector?