I am around 6.3 or probably 6.5 BPEL and all my life I have always had petite girls except one who was taller than me and had wide pubic area, apparently the only one who seemed to take me in without any complaint and she enjoyed it with me a lot more and later told me point blank "Yours is not too big as to cause pain, I would prefer your size all the time". Almost all the ladies I have had at one time complained about me going too deep and told me to stop when it got painful, and one of them used to avoid having sex with me since she would complain that am always banging her to almost causing pain, I once had sex with her and the following 2 to 3 days she complained of pain and could not pee properly. That alarmed me a lot since I was too naive by then (I have learned a lot here in this forum and I am more informed now, thanks PE big time).
My current lady has never complained about my size (Save for once when she told me to goo slow in deep penetration, we resolved that as I would NEVER want to cause pain to my girl). But she is just very comfortable with me and we can even have sex as much as six times in a row. Though I am PEing to increase my size to a minimum of 7 inches NBPEL.
From my experience whether you cause pain or pleasure it has more to do with how you are doing it mostly than your size, but it is also true that some women will take a 9 inches without complaining and others even 6 inches is just too much!