[effjay60]

Synthetic lubricates better and leaves a film on engine parts helping prevent engine wear at startup. The Harley guys at work say it runs 10 degrees cooler in their bikes. It's better hands down. It's more expensive hands down. One more benifit is that synthetics do not contain any sulfur. Refineries cannot remove 100% of the sulfur from their product. Sulfur combines with water vapor to form sulfuric acid (icky) which is why you should change your oil periodically despite milage.