I will start by saying that I know that people have different preferences and this is just the way it is.
Lately, I had this discussion with lots of men and I also have read on some forums. Men seem to dislike the idea of fake boobs, they just don't like them. But if so, why do so many of you check them out in magazines or on TV? You know that the boobs are fake and you stated that you hate them. Then you check them out. It really does not make any sense to me. I don't know if it is just me, but it really pisses me off sometimes. Personally, I have small boobs, and I do have insecurities about my breast size. It might be because of this. But, however, I wouldn't do a surgery for bigger breast.
I agree with Demoin. It is absolutely subjective. I, personally, never touched fake boobs that I was aware of, but if it feels natural and looks nice, I don't see a problem.