Update: Okay, I should read survey methodologies more closely. A fair group of these women were recruited through classified ads in an anti-circumcision newsletter. Selection bias much? So read this for fun, but it's probably bunk.
Frankly, I find the "smegma is gross" argument an enormously powerful brief in favor of circumcision. But pleasure matters, too. Normally, I've heard that adults who are circumcised don't notice a change. Julian Sanchez has heard differently. So I went in search of some rock-solid data. As they say, "you can stop a man with a study."
But you can depress him. I didn't quickly come across any research on differential rates of pleasure experienced by those circumcised late in life. What I did find is a study on rates of pleasure women experience from "altered" and "unaltered" penises. And there, the data was clear: Women prefer uncircumcised penises. And this is true on just about every metric. Not only do they furnish more orgasms and offer more pleasure, but they offer less vaginal discomfort and premature ejaculation. "During prolonged intercourse with their circumcised partners, women were less likely to 'really get into it' and more likely to 'want to get it over with.'"
This translates into the emotional realm, too. Women were more likely to report feeling (deep breath) irritable, unappreciated, sexually violated, out of sync, uncared for, bitchy, guilty, and even "incomplete as a women" with circumcised partners. And that's only a partial list. As the study says, "the consistency with which women felt more intimate with their unaltered partners is striking." And there's not even bias towards currently circumcised partners. "The circumcision status of the most current sexual partner did not alter the findings." report the study. Nuts!