One difference between anal and vaginal which is consistently reported by people (other than the enhanced pleasure) is the greater intimacy that anal sex provides.
Cosmopolitan mentions the intimacy factor when discussing why guy’s are obsessed with anal sex:
On an emotional level, a guy might be into anal because of how intimate it is
the special attention to preparation, serves as an intense form of foreplay, heightening excitement, extending the sexuality and sensuousness of the encounter, and, not incidentally, increasing the chances that the woman will have an orgasm, through the extended foreplay and stimulation.
While also recognizing that:
When a woman is willing to engage in anal sex with her lover, it is usually coming from a place of significant trust and love of her male partner.
As is often the case, the comments are usually more revealing than the article itself. This 25 year old women says:
The most arousing thing to me is experiencing my husband’s arousal
One blogger often discusses the subject of intimacy in anal sex as she explores the reasons for it.
Whatever the reasons for this greater intimacy, many more people are turning to anal sex in order to enjoy greater fulfilment, forge a deeper connection with their partner, or simply because they are disappointed by the superficial release that vaginal sex provides.