非合成油 is almost like a commodity. If the price is

about the same,there is very little difference in the base oil property. Some may claim the cleaning power is better. But that means you may want to change oil faster, at least the first oil change. Some claims longer life, but if you follow regular schedules (3,000-4,000 miles/most cars), they are no better. So it is very hard to define A oil is better than the B oil if they are all group 2 stock oils.