I have no idea. Never had the chance to see one on person. I heard it tastes like a regular sugar apple. Maybe you mean does a seedless banana/watermelon taste better than a seeded banana/watermelon? Probably, since your whole mouth is full of the flavor without those pesky seeds.
I'd imagine cherimoya will always be better than sugar apple and atemoya. The Spanish researchers are trying to create seedless cherimoya out of seedless sugar apple. They don't care about all the seedless atemoyas they will make in the process.
So if you pollinated a cherimoya with pollen from the seedless sugar apple, there's a chance that the resulting atemoya will be seedless as well.