2nd Level Dread Commando give Armored Ease 2, reducing the penalty for all armors by 2.
4th level gives Armored Ease 4, reducing the penalty by 4 (they don't stack).
So you can wear any Mithral (-3 ACP) armour with and have no Armour Check Penalty. Even half-plate and full plate.
The Guerrilla Warrior Feat in that book also reduces the Armour Check Penalty for light and medium armours by 1, and means Hide and Move Silently only cost one skill point even if cross class. Making it a good way to meet the class requirements of Dread Commando without needing to take levels in Rogue.
Guerrilla Warrior and Mithral armor you can negate most of the ACP in medium armors, and with 2 levels of Dread Commando you can wear Full Plate with no ACP.