Abstract-This paper tackles the problem of designing an effective user interface for a multi-robot delivery system, composed of robots with wheeled bases and two 3 DOF arms. There are several proven paradigms for increasing the efficacy of human-robot interaction: 1) multimodal interfaces in which the user controls the robots using voice and gesture; 2) configurable interfaces which allow the user to create new commands by demonstrating them; 3) adaptive interfaces which reduce the operator's workload as necessary through increasing robot autonomy. Here we study the relative benefits of configurable vs. adaptive interfaces for multi-robot manipulation. User expertise was measured along three axes (navigation, manipulation, and coordination), and users who performed above threshold on two out of three dimensions on a calibration task were rated as expert. Our experiments reveal that the relative expertise of the user was the key determinant of the best performing interface paradigm for that user, indicating that good user modeling is essential for designing a human-robot interaction system meant to be used for an extended period of time.