With QRISK.org I reckon I have cut my risk of a heart attack or stroke in the next 10 years from 7.8% to 6.3%, a 20% reduction. I've had no side effects.
I can't be sure of course that it was the statins that caused the Cholesterol/HDL ratio reduction. Changes in my diet and / or exercise in the last year might have helped too.
Before I took Statins (3/1/13)
1 Year after taking Statins (21/3/14)
What's your QRISK?