Today the application server race is completely different from few years ago.Websphere is the number one for big projects and, as usual, is late and is still not Java EE 5 compatible. On the other hand, just when companies had started to use open source with JBoss, JBoss has left the race and version 5 is still in beta.Weblogic, the very innovative company (you should look at Weblogic Virtual Edition) has been bought by Oracle. God knows what will happen. GlassFish is by far the best open source Java EE 5 app server. But people still don’t know it well. And if some do, they immediately remember the previous reference implementations made by Sun (the ones used to play with the Java Petstore) that were not usable for real life project. GlassFish is.