Sorry strato but I'd have to disagree on a couple of things.

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.

The only disadvantage of rings is that it takes much longer to run in enough to be flyable and a totally different running-in technique has to be used. Ringed engines are far more dirt tolerant.

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