I would of said IJ but let's face it. every main Gundam now has a beam sheild which makes IJ weapons useless. but Aegis now there is a deadly gundam, I have to agree with FelixZeroAlastor being limited power supply. so best unit used so far by Athuran would be Aegis. I am not sure about IJ I have to see that suit in action but for now Aegis.