Advances in commercially-available ASR technology have enabled the deployment of “How-may-I-help-you?” interactions to automate call routing.  While often preferred to menu-based or directed dialog strategies, there is little quantitative research into the relationships among prompt style, task completion, user preference/satisfaction, and domain.  This work applies several dialog strategies to two domains, drawing on both real callers and usability subjects.  We find that longer greetings produce high levels of first utterance routability.  Further, we show that a menu-based dialog strategy produces a uniformly higher level of routability at the first utterance in two domains, whereas an open dialog approach varies significantly with domain.  In a domain where users lack an expectation of task structure, users are most successful with a directed strategy, for which preference sc ores are highest, even though it does not result in the shortest dialogs.  Callers rarely provide more than one piece of information in their responses to all types of dialog strategies.  Finally, a structured dialog repair prompt is most helpful to callers who were greeted with an open prompt, and least helpful to callers who were greeted with a structured prompt.