Originally posted by downunder
Some manufacturers offer the option of either ringed or ABC (OS do this with some of their engines) and in that case there's no difference in price or power. Blow by is virtually non existent under running conditions once the ring is properly run in and seated.
I've never worn out the rings in any of my engines even after a LOT of use so it's hard to say how long they last 
I stand corrected on the price, but if it isn't due to blow-by, then why do they produce less power? Same fuel, same prop, same engine manufacturer, 1000-2000 RPM less.
I've never seen worn out rings either, but I DID say they lasted longer.