I used the federal mogul sealed power non file to fit rings(original pistons, etc.), and they have worked fine for years. If I had to do it again, I'd probably investigate the Total Seals, however they are expensive. I have hearrrrrd they wear the cylinder out faster, but can't say for sure.
Could be rings, however, at 125k, my original rings looked okay, except they had a large amount of carbon built-up,, so mileage may not be a big factor. Blow-by could be(probably) valve seals/guides too.