Demons and Bot are probably my favorite MM class.
But i think you answered your own question.
If you want pets that wont run out of Faraday Cage
and able to play at max setting (which i assume to be */8)
and provide debuff against tough targets (-regen)
then the answer should be Bots.
At */8 play it is all about AoEs, and that is where the Bots shine.
With Demons it will be more of kill them one at a time playstyle that is counter productive to a */8 setting.
Not to mention all of the running in and out of melee.
That is just my take, and others might have a different and better take.
But if in doubt, make both!!! 🙂