In this paper, a validation and an experimentation of the use of graded BDI agents is reported. This agent model has been proposed to specify agents capable to deal with the environment uncertainty and with graded attitudes in an efficient way. As a case study we focus on a Tourism Recommender Agent specified using this agent model. The experimentation on the case study aims at proving that this agent model is useful to develop concrete agents showing different and rich behaviours. We also show that the results obtained by these particular recommender agents using graded attitudes improve those achieved by agents using non-graded attitudes.