I just purchased a Shindaiwa EB-8510 backpack blower. The dealer told me to make sure I used Shin One oil to keep the warranty valid. But, from my readings one this site it appears that over time my blower will begin to run rough because Shin One is not a premium oil. It appears that Tanaka oil is a better quality oil. Personally, the "don't use any oil but Shin One" seems like hype from Shindaiwa so you'll be forced to buy their oil...but I don't want to void my warranty...then again how could they tell if I used something different??