I don't like it when gas stations have a different price for cash and credit, especially when it is hard to tell the price until you get in the station. I usually go to stations that have the same price because I have the Bank of America Cash Rewards credit card that gives 3-5.25% cashback on gas depending on how much money you have with Bank of America.
Every once in a while I go to a gas station with a different cash and credit price and I still pay credit. The difference is usually 8-10 cents a gallon. When gas is $3.00 a gallon, it is still a better deal to pay by credit card and it is much easier.
I live in New Jersey and gas prices are approaching $2.00 in some areas. The difference between the cash and credit price is the same 8-10 cents a gallon. That changes the entire equation. If you are getting 3% cashback on your gas purchase, that's 6 cents a gallon. If you pay 10 cents a gallon for the privilege of using a credit card it's actually more expensive.
Every person's situation is unique to their credit card and the price of gas in their area. The moral of the story: As gas prices decrease and the difference between cash and credit does not change, there comes a time when it is no longer cheaper to pay with credit card.