I have tried both side by side several times, sometimes I prefer one over the other, I remember after the second harvest of my Achachairu I thought of getting rid of if because fruit was too acid, for some reason reasons I didn't do it and next year wow! Fruit was sweet! Achachairu is sweet /tart as Mexican Garcinia, the flavor and texture are different, Achachairu is like Spicy while MG has more of a lemony citrus flavor maybe is the reason that locals call it "limoncillo" about texture Achachairu is kind of cottony flesh like the mangosteen while MG is more like soft and creamy like an Ice cream,
I would say the balance between sweet /tart would be the same, Achachairu rind is thick and not edible out of hand while MG is thin like tomato, as far as size you can see the picture,
I would plant both if I were you..
