Despite being a profession dedicated to the empowerment of service users, empirical study of mental health social work appears dominated by the perspectives of social workers themselves. What service users value is less often reported. This study, authored by a mix of academics and service users/carers, reports a Best–Worst Scaling analysis of ten social worker ‘qualities’, representing both those highly specialist to social work and those generic to other mental health professionals. Fieldwork was undertaken during 2018 with 144 working-age service users, living at home, in five regions of England. Of specialist social work qualities, service users rated ‘[the social worker] thinks about my whole life, not just my illness’ particularly highly, indicating that person-centred approaches drawing on the social model of mental health are crucial to defining social work. However, service users did not value help accessing other community resources, particularly those who had spent the longest time within mental health services. Continuity of care was the most highly valued of all, although this is arguably a system-level feature of support. The research can assist the profession to promote the added value of their work, focusing on their expertise in person-centred care and the social model of mental health.