JBoss deployment and configuration is easy and fast. This leads to lower cost and faster deliveries.
Jboss gives you lot of flexibility around performance tuning options to better suite your application needs.
It is modular and cloud ready. This can be installed on-premise and cloud with equal ease.
I specifically love it's integration with mod_cluster. It is a smart httpd based load balancing component that listens to incoming requests on web server using httpd and then intelligently routes the request to Jboss hosts.
Jboss CLI is a great tool but we had trouble using it to get values that are displayed on Jboss GUI. It also has limitations parsing the applications.xml files and we had to use a mix of jboss-cli and linux bash commands to automate certain application administrative tasks.
JBoss doesn't really provides performance tuning recommendations. It would have been nice if it could learn from the current demand vs current settings for things like connection pool, server configurations, garbage collection etc.
Out of the box performance tuning. I have often felt the need to tune things like connection pool, server configuration, garbage collection for performance. It would be nice if JBoss were able to set some of these out of the box and require administrators to just turn on/off the feature.
Jboss-cli is a good command line utility but is still a little complex to learn. It also has a limitations query JBoss command line for certain values that you can see on the JBoss GUI interface.