Like this bud here. (second photo) It got pollinated early enough that all the seeds are right at the flowering base, and the rest of the buds are essentially seed free for the vast majority of the buds. This is the White Widow Auto x Frankenstein, I had 2 of these plants, I believe. I guess what I'm saying, is if stuff is pollinated early, and efficiently, your going to have not only mature seeds, but pretty damn good flowers, that are not much different from seed free cannabis, maybe a notch down at most.
But when seed saturates a flower, it taps much of it's size, resin production and potency.
The bud on the left has seed all in it, the bud on the right had seed, but only at the base. One is kinda larfy and soft, the other is a solid nugget. Both produce good seed, but the one on the right is more useful IMO.