This paper presents an evaluation of the speech output component of a smart home system developed under the European INSPIRE project. In particular, it is investigated how the 'personality' of the system which is conveyed by the output speech is accepted by the user. Three different metaphors are compared: An assistant visualized by a talking head, an invisible assistant, and multiple intelligent devices. The results show that a personal assistant metaphor leads to more homogenous judgments for the individual voices. Potential reasons for this finding are discussed.