From official guides:
If the controller does not implement a method with the same name as the action in its actions object, the action will be sent to the router, where the currently active leaf route will be given a chance to handle the action.
So what are pros & cons of defining actions methods in controller and defining actions methods in route? As i can see guides doesn't talk about that. Defining in controller can be "faster" in sense of preventing action bubling.
Good question, although perhaps not an ideal fit for the SO format.
The simple answer is, put routing-related actions in the router, and controller/model-related actions in the controller.
If you find yourself calling this.controllerFor in the router action, or this.get('target') in the controller action, there's a good chance you've misplaced the action.
Transition-related actions are often a good choice for putting in the route. Actions such as modifying or saving a model likely belong in the controller.
Remember that actions bubble up from the leaf routes to parent routes. So if you want to define an action that applies to a group of children routes, it makes sense to put that in the parent route.
