A good review article on the current state of our knowledge, focussing on the entire spectrum of sexual enjoyment and not just erectile function. They make clear that the enjoyment of sex is a product of many factors, including pre-ADT sexual function, habitual sex frequency, testosterone (amounts needed vary widely), erectile function, partner enthusiasm, sexual aid use, non-penetrative intimacy, physical fitness, sleep, masculine self-image, depression, and novelty.
Many comments on how things for gay and bisexual men can be different (e.g., greater importance, ejaculation, openness to sex aids and novelty)