What big ed said about bushings. Compare that to the number of times you read about rusted bearings.

As for ringed versus ABC...treated properly they'll both last about the same time but ringed is far cheaper to fix when they eventually wear out. Powerwise there's virtually no difference if the engine has an option for either like some models of OS have. The only limitation with rings is they can start to flutter in the groove over about 20,000 revs .