Yeah it's not even close. Void all the way. If you want to use Modok on defense he really doesn't need to be awakened but help when he's on offense a little more. That said Void is amazing and will serve you well.
Void arena is coming up if you are talking about 4*. You should grind him out if possible instead of using the AG on him. Then you can use the AG on Modok to make him even better for AW defense.
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EDIT: Just saw your second post so NVM.