Aims: The aim of this exploratory analysis of European Quality Audit of Opioid Treatment data was to identify areas of improvement for current opioid maintenance treatment (OMT) approaches. Methods: Factors facilitating treatment entry, retention and refusal were compared between 8 European countries and between OMT patient (OMT-P) and active opioid user (AOU) sample groups. Both groups were divided into those who had never had OMT before (un-experienced OMT-P (n = 573) and AOU (n = 360)) and those who had been maintained at least once prior to this investigation (experienced OMT-P (n = 746) and AOU (n = 377)). Results: The European comparison showed that motives for starting OMT vary distinctly between countries (p ≤ 0.001). Transnationally, experienced AOU reported concerns about their ability to follow treatment rules and negative treatment experiences as decisive reasons for staying out of OMT. Greater flexibility, less pressure to reduce their treatment dose and greater treatment structure were ranked significantly higher by experienced compared to un-experienced OMT-P as factors that might facilitate treatment retention (p ≤ 0.05). Conclusion: Increasing awareness of potential shortcomings of OMT delivery systems is crucial to optimally match treatment approaches to patient needs and also to reduce the considerable economic burden of addiction to society.