I use Tasker but I see no need/reason to use Tasker for controlling your A/V equipment - maybe I can learn something?
My usage, and thought process...
Tasker is best at automating phone tasks & sending info to external systems (like Vera - using Authomation)
Vera is far more robust, and clearly better, at controlling the home (lighting, A/V, etc)
Things I use Tasker for:
notifications to Vera when we are in proximity of a location (home, gym, etc) or leaving that location
NFC notifications to Vera
Why do you need Tasker for Harmony?