The impact of variable implementation of the Assertive Community Treatment (ACT) model on patient outcomes is increasingly recognised. We conducted the first study of four established Australian ACT teams, examining team composition, processes and model fidelity, using previously validated questionnaires. Demographic and clinical details of patients and their own experiences of ACT were gathered from staff. Associations between burnout and work experiences were examined. All teams were ACT-like (mean DACTS score = 3.7, SD = 0.3) with few significant patient differences between teams, except diagnosis (schizophrenia 61-93%, co-morbid substance abuse 16-33%) and proportion living alone (23-72%). Clinicians were fairly satisfied, but inter-team differences in staffing profile and experience emerged and one team scored highly on emotional exhaustion. Increased burnout was associated with greater stress due to taking a team approach. Inter-team differences suggested that attention to effective team working and leadership, as well as model fidelity, may be warranted.