I am working on a project in which the data acces layer is a collection of a Facade and DAO object both of these are JavaBeans, the web tier access the DAO methods via the facade. The data access object is implemented as a Java Bean with calls to a bunch of stored procedures which implement the data aggregation logic, the system works fine and is pretty fast, now the question is there any benefits that i can get using EJBs, what are those (in this scenario).
If it's working, don't try to fix it...
Regarding future requirements, however, EJBs might come in handy. If, for instance, you need to cluster your application the EJB container does a gazillion useful things for you (think distributed transactions, caching).