I have them both grafted in on the same tree, but only LZ flowered this season (holding 2 fruit now). It's pretty stark having them both side-by-side, the LZ issues are apparent year-round. OS bark is clean while a few feet away LZ bark is constantly covered by dark, sooty splotches (guessing it's some type of mold). LZ flowered twice last season, but PM wiped out the first flowers. I dedicated myself to spraying with sulfur on the second wave, managed to get a bunch of tiny fruit, but then I went away for a week at the exact wrong time. Several heavy rains the first two days were followed by high humidity and low winds the rest. It was a sad sight to come home to, PM once again wiped almost all of them out.
Next season the OS should flower (grafts will be 2+ yrs old), hoping to have a true head-to-head taste match-up.