The ROBOCARE Domestic Environment (RDE) is the result of a three-year project aimed at developing cognitive support technology for elderly people. Specifically, the domestic environment is equipped with sensors, intelligent software components and devices which cooperate to provide cognitive support to the assisted person. The ROBOCARE interaction capabilities have been concentrated in a robotic mediator who acts as the main communication channel between the users and the intelligent domestic environment. This paper presents an evaluation of elderly people's perception of assistive robots and smart domotic environments. Results show how the acceptability of robotic devices in home setting does not depend only on the practical benefits they can provide, but also on complex relationships between the cognitive, affective and emotional components of people's images of robot. Specially, we analyzes a number of evaluation criteria related to the robot's aspect, the way in which it communicates with the user, and the perceived usefulness of its support services. Among these criteria, the paper proposes and reports an evaluation of how perceived frailty, with reference to both health in general and fear of cognitive weakening, more specifically, can influence the evaluation of a potential aid in everyday life, namely the robotic assistant. The paper also provides a discussion which can be useful for the design of future assistive agents and socially interactive robotic.