EventAggregator vs CompositeCommand

Question

I worked my way through the Prism guidance and think I got a grasp of most of their communication vehicles.

Commanding is very straightforward, so it is clear that the

Answer 1

Additionally, there is one more important difference: With the current implementation, an event from the EventAggregator is asynchronous, while the CompositeCommand is synchronous.

If you want to implement something like "notify that event X happened; do something that relies on the event handlers for event X to have executed", you either have to do something like Application.DoEvents() or use CompositeCommands.