My 2 cents worth - My cousin has 9" and says that letting girls know that always gets them, particularly if they have not been with a larger guy.
But...and there is a but...he told me that the vast majority find the pounding to the back of their vajajay so painful that he cannot finish and so usually does not come at all. And he said, his not coming is also unsettling to the girls. So sex usually ends awkwardly for him, unless the girl is one of the few that enjoys the pounding.
Having only 5" myself, I now have new appreciation for non p4p girls always wanting to cuddle after sex (in my experience).
My Bio Page - Kansas City Metro
