There are three major gas companies around where I live: Petro Canada, Shell, and Esso. I am currently using Petro because it has something called "Petro-Points" which you gain every time you fill up and you can use those points to get free gas or a chocolate bar.
What I want to know is: is there a company that distributes the "best" gasoline? A new Shell station popped up across the road from my local Petro and when I think of Shell, it makes me think that its gas is somehow of a better quality than Petro and Esso, so I find my self in the Shell sometimes. Some people even stated that when they switched to Shell, their mileage improved (and vice versa for other companies).
I think it has something to do with how some companies put special "additives" in their gas (which can be better or worse).
So, which one's best? And what are your experiences with different companies?