This paper presents an in-depth evaluation of user adoption of the Multi-Track Music Machine (MMM), an AI-based music generation system. We conducted a three-stage mixed-methodology study to measure usability, user experience, and technology acceptance among two groups of professional and amateur composers using the MMM-Cubase (MMM-C) plug-in integrated into Steinberg’s DAW Cubase. Results showed that usability and acceptance scores were positive, with users experiencing novelty, surprise, and ease of use in using the system, but reporting limitations in the interface’s controllability and predictability when creating music. There were no significant differences between the two user groups.