Enterprise JavaBeans is a widely-used technology that aims at supporting distributed component-based applications written in Java. One of the key features of the Enterprise JavaBeans architecture is the support of declarative distributed transactions, without requiring explicit coding. In this paper, after a brief introduction of the concepts and mechanisms related to the EJB Transaction Model, we provide guidelines for their consistent use. We then evaluate the EJB Transaction Model on an Auction System case study. The encountered limitations are presented, and possible work-arounds are proposed for the auction system. We conclude with suggestions for enhancing the current EJB Transaction Model.