I tell girls that it really comes down to what makes them happy, however my honest opinion is that natural boobs are better, in keeping with my sex positive, body acceptance, philosophy.
As a shooter, I think that models with implants tend to look better clothed (bikini/lingerie), compared to nude. The opposite tends to be true with implants.
While some individual photos may benefit from augmented boobs, if the photo set is viewed in total, I find natural is easier for me to produce a consistent set/scene that tells a story (my style of shooting).
I can usually instantly spot implants, and given my experience, I prefer the touch of natural boobs, and how each set is different from girl to girl.
I'm more into a model's face and frame (overall body), than her breasts (I like a nice B/C cup, with perky/puffy nipples).
ADG