I kind of doubt that 95% estimate. Lots of men I've talked to, including myself, have a PREFERENCE for large breasts, and that's OK. It's not a make or break thing, but I do like them. That being said, I don't brag about sleeping with anyone.
As for how it affects sex, I do find the visual of them bouncing around during sex exciting, especially when they're all up in my face. There's also the option to titty-fuck, which is pretty much impossible with any woman under a D-cup. My ex-wife was a DD, and pretty much the only thing I miss about having sex with her was her ability to wrap her boobs around my balls and base of my dick while giving me a blowjob. The current wife's C's can't do that. haha
All that said, the older I get, the more I'm becoming an ass man anyway. Same deal though, I prefer a big, round ass.