Once my clan has unlocked the Outbreak Prime quest chain from turning on the 5 monitors during Wrath of the Machine, is there any point in searching out the monitors on subsequent runs? Or is this all they accomplish?
The only reason to activate the monitors in the raid other than to start the Outbreak Prime quest is to get to the chest that is in the same area as fourth monitor. This chest is guaranteed to contain an exotic engram once per character.
So it makes sense to activate the monitors (or at least the fourth one) until all of your characters have opened the chest with the fourth monitor.
Once you have gotten the Outbreak Prime quest from the chest underneath the Aksis room, there isn't really anything to be gained from doing the monitors again. Unless you want to do the entire quest over again on each character.
The fourth monitor inside the cube has a chest that grants an exotic engram ONCE per character. But other than that, why not just take the Outbreak Prime out of your exotic kiosk if you have already gotten it and just infuse it up?