Naturally
Breasts by their very nature are firm when younger and slowly change shape through maturity. The sight of breasts made falsely firm and round is ugly to me and a natural 'sag' is much better. I also don't particularly like over large breasts which somehow feel unreal to me (Large is fine, it's out of proportion big I mean). Pert is pretty, small is sweet. And a nice firm nipple is good to eat (gently of course). Some people will differ from me but this is what I prefer to see - naturally.
I am with you all the way there, old chap. No silicon-enhanced breast is ever as nice as the real, unaltered thing, and there is also the question of the risk to the woman's health. There was a terrible scandal a few years back where a French manufacturer of silicon implants was found to have used inferior, and medically prohibited, silicon and thousands of women had to have further surgery to have them removed.
Mastectomy patients excepted, of course.