While we cannot speak to the quality of other essential oil companies, our essential oils are of the highest quality. Our President Dorene Petersen hand-selects each essential oil from ethical, sustainable distillers, many of whom are organic. She has also visited many of these distillers in person.
Quality is one of our passions at the Apothecary Shoppe and ACHS, so we are very conscientious about how our oils are chosen. You can read more about our philosophy and how Dorene chooses our oils here: http://www.apothecary-shoppe.com/pages/the-quality-promise
Dorene and other faculty at ACHS have also developed a number of blogs and webinars on this topic:
https://achs.edu/about-us/research-papers-ebooks/
Best of luck in your research on essential oil quality!