It depends ... (yes, another long ProfV dissertation)
First off, as you've heard me in countless other threads, I want an wide, full, hourglass figure. I'm a selfish male pig, it's just what I want. Everything else around that, if it pleases me, is a "bonus." But at the same time, because I selfishly insist on a woman with a hourglass figure, typically wider and fuller, she often has a natural C cup set of breasts at a minimum, and most are D+ cup with a good amount of hang.
Secondly, when it comes to "window dressing" with her clothes on, a woman should do whatever she feels she needs to be comfortable. In reality, that does not always mean she needs implants, but she can use inserts and other things inside of her bra for added bust. I wish more women would do that, and then find themselves a man who loves them for them, instead of trying to please every picky man out there.
Side Note:In fact of which I've only noted Erica Rose Campbell -- who is hardly "mega-busty" but just "amply bust" -- seems to have what one could term "universal appeal" among men. It's virtually impossible to get every man to see you as "acceptable" -- especially with how cruel men are in public, based on what (at least the US) TV and other mainstream media seems to set as a "standard."
Third, the only time I have great concern about "fake breasts" and prefer "natural" is when I'm intimate. I need a woman with naturally soft breasts, because the sensation in my hands, around my manhood or even when brushing up against any part of my body, as well as when my mouth attempts to engulf a portion of them, just needs to be such. If my lover has an oral fixation, then the best lover is one with C+ cups who knows how to both wrap them around my member and provide constant oral stimulation -- it's just unbeatable for foreplay, as well as climax if she is so inclined to please that way too. So for a woman not to have natural mammary glands, the absolute softest part of her body with no supportive bone or even cartilage, that are not, is just completely undesirable to me when it comes to physical intimacy.
Side Note: It should also be noted that having a long-time lover with natural breasts can be a very, often lifetime, captivating existence. As she ages, her breasts soften and hang more, which can be a great attribute depending on how you make love to her. Furthermore, as you age with her, the more she knows your sexual body language and reactions, without any discussion on the fact. Personally for myself, after 10 years of marriage (and 13 years with the same woman), her prowess in the sack has been steadily increasing without any drop, as she uses all of her body's natural changes with her ever increasing knowledge of my body's animalistic reactions to fulfill erotic dreams I have never had until she just introduces directly me to them with I receiving them. In fact, when people speak of women who would just "fuck your brains out," I instantly want to scream at them to get married and focus on one woman based on my experiences -- something people would probably laugh at.
Now with all that said ...
back in the '90s, there were many silicone and saline women I found very attractive. Dakota Kelly for one, my all-time favorite pin-up, because her body was so wide, hips so full, yet her body so slender. But even other, more enhanced looking women like Nikki Knockers and Traci Topps were very attractive to me because of their hourglass figures. Hell, even Pandora Peaks not only grabbed my interest -- not because of her breasts at all, but because of that tight, 22" waist and extreme curve of a body with that unique little mouth of hers. More recently I like Ourei Harada, who has clear had enhancements and her body is definitely bigger, for her same, little, petite mouth.
Now would I have all the non-intercourse "fun" and "pleasure" to the same levels of someone like my wife with natural breasts? Probably not. But would they be unbelievable lovers for intercourse? Ironically, probably better (at least from my preferences and viewpoint) than thinner (much thinner than I like) women with even natural, even very large (for their frame) breasts. So it all "depends."
Personally, to conclude ...
I think the world has changed on the "female proportion" (let alone the "clean shaved" requirement), far more than just the whole "bust" argument. To me, not to have a woman with an ample abdomen and hips to take my spearing manhood, let alone not to give me a thick set of bush (which should match her raven top) for which to spear through (which I liken to "the best crotchless underwear"), is more of a concern for my likes. That's just as bad, in my view, as a lover with fake breasts -- but for clothed "window dressing," neither really matters.