I can't speak for the folks in the U.S.....but we have 4 major brands in Ontario (sunoco, shell, petro canada & esso)....they evaluated the quality of them.....by far the 2 best in order were sunoco & shell. The other 2 (especially esso) had a much higher sulphur content (PPM). Sunoco & Shell are the only 2 I use up here......I like Shell, Chevron & Texaco south of the border.