Over the past year, I've strictly filled up at Shell b/c I feel like it's the best option around my area. Some places used blended (up to 10%) gasoline/ethanol and I never liked that. Around the first of the year, the Shell stations that I frequent all posted stickers about their gas containing up to 10% ethanol. Although I didn't like it at first, I've realized there's no way to get around it. I don't remember if this is correct or not, but I think a law may have been passed either locally or state-wide about all gases now have to contain an ethanol blend.
I need to round up all my records and see if my gas mileage has decreased. I track every single tank of gas I buy so I should be able to tell. Although, with summer blends coming back, it might offset any drop in MPG that I was getting with the blended stuff.