If PET didn't have the light-piping issues I'd much rather use it over an acetate base any day of the week. I am not concerned with jamming cameras with it, so that's not an issue for me. But polyesters have a very long life-time. However, if PET for all roll films meant having to screw with some kind of REMJET layer, then know, I'd rather use acetate.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.