i grafted a couple of my trees.
i have to say the fruit from my large tree is as good as the graft selection.
the seed-grown is a bit more acidic, but just as sweet.
the fruit "quality" seems to be better on the grafted variety.
(each fruit ripened perfectly, no blemishes etc...)
i didnt see much difference in seed to fruit ratio, or even size.
that said, all the grafts took (8 total i think)
and i am not an expert grafter.
i really like the fact they ripen at different times.