We just completed a project for a US client which involved message queuing

A few short guidelines of when to use message queuing can help to clarify the decision to use it or not:

If the application you are communicating with is not running at the same time as your application, use message queuing…

If the message is important and will cause problems if it is lost, use message queuing…

If your application is not always connected to receiver application, but still needs to be functional, use message queuing…

And if you perform many communication tasks with other applications asynchronously, and may or may not care about their response, use message queuing