The increase in the number of safe and effective ED treatments highlights the importance of patients’ preference when choosing a therapeutic option. Several studies assessing these preferences are now available in published literature. This article aims to review and discuss the studies on patients’ preference and the data concerning the reasons for preference for one PDE-5 inhibitor over another. A PubMed search was conducted for manuscripts published within the last 10 years containing the search items ED, preference, sildenafil, tadalafil or vardenafil. Selected articles were discerningly reviewed and summarized (design, limitations and relevance). The articles selected were peer reviewed publications on patients’ preference and ED published in medical literature since 2000. Preference studies that include either two (tadalafil and sildenafil) or three PDE-5 inhibitors (tadalafil, sildenafil and vardenafil), showed that the majority of the patients preferred tadalafil versus either vardenafil or sildenafil. As the treatment of ED has evolved, patients’ preference has become an important aspect of ED therapy, 52–65% of patients prefer tadalafil versus 12–20% vardenafil or 8–30% sildenafil. All founded studies have serious limitations, particularly in terms of dosing differences. Preference for tadalafil was mainly because of the longer duration of action that increases patients’ freedom in sexual life. There is a consistency in patients’ preference for tadalafil over sildenafil or vardenafil across the studies reviewed.