My Guthrie and odum plums are starting to ripen, so here's an update.
Guthrie-no disease so far in 3 years with no spray. Plum curculio hit pretty hard, but this just encouraged me to do some needed thinning. Incredibly vigorous, I've already summer pruned twice to try to control height. Very heavy fruit set on some branches, almost none on others despite blooms. Didn't see many polinators while blooming. Ripening fruit tends to crack in this very wet weather we've had, but hasn't rottted. Fruit soft, juicy, sweet and tangy.
Odum- mostly the same as Guthrie but only 5% of the fruit set. Ripening a a couple of weeks behind Guthrie, so I haven't sampled any yet.