It would depend on the settings in each of course and the rendering intent used for testing. Even if true, the new i1P engine is significantly better and smoother and there’s more to all this than a tad more saturation. I’m not going back to ProfileMaker Pro for that.
But what i see is that the icc generated by pm5 has a higher dmax than the one which made by i1p even i use the same measurement data measured in i1p. So right now, i do sometime use pm5 to create icc with. My custom made target to get a deeper black for some specific jobs. But like what you said, i still use icc which made by i1p for 99% of my jobs.