sythetics were developed for use in the alaskin oil field..those are some EXTREME conditions..from -60 to working temp right now. conventional oils could not withstand the extremes and were useless...so without going into major detail..if its better up there..its better in your engine. Brand names.....well..whats better..wall mart or target...pretty much all the same..Mobile 1 seems to be the most often used here!