Hi Samba-
Volumes have been written on this subject, and for every point made on the subject, there are three bloggers waiting in the wings with a counter argument.
I have already expressed my thoughts on the value of standards, but as a further point, I will say that if you like Spring, you could frame the issue not as "What about EJB3 vs. Spring" but "What about EJB3 *and* Spring". Spring is a perfectly good light-weight framework, and EJB3 has implicitly endorsed it by incorporating some of its core concepts. However, there are legitimate concerns about Spring's scalability, and it doesn't offer remoting support, something that is built into EJB3. These issues can be addressed, in cases, by wrapping Spring in EJB3, to take advantage of the EJB3 container's built-in services. The EJB container, and its surrounding
Java EE server, in the context of an vendor-specific application server, offer a wide range of enterprise features that justify their use, particularly for large-scale deployments.
Beyond that, I'll leave this issue to other posters, or the legions of bloggers that are a google search away...
Regards,
Jon