I went through the virtual switch vs momentary tile configs last night and settled on the momentary switch since it was a pain to put in the logic which would keep the Harmony device states synchronized with the real device states. However, I wasn’t happy with “Turn on Exit” or similar unnatural commands so I made a virtual switch (not momentary tile) for the power off command and every time I ask for one of my “turn on” activities (DirecTV, Chromecast, or Miracast) it turns on the “TV” virtual switch, which isn’t tied to any event. Then I can say “Turn off the TV” and it all goes off.
There might be a better way to do this but it’s working well for me.