The Cybran ACU was the staple command vehicle for a Cybran commander throughout the Infinite War. This ACU was issued as standard to all Cybran commanders.
The ACU plays as an important role during combat. Building structures quickly and, when fully upgraded, can be a formidable weapon if used correctly.
ACUs are also very important to protect, the destruction of one, causes a nuclear explosion. So despite its resilency, the commander should always make sure the ACU is well protected. But if core dump is researched, the threat of a nuclear detonation is averted.
The Cybran ACU is known to be the most powerful combat ACU when fully upgraded. Many players have commented on how it's "god-like" and can take on 100's of basic units on it's own.
However the Aeon ACU when fully upgraded is the only ACU able to on a 1 on 1 battle to defeat a Universal Collosus and survive. This is not true. A fully upgraded (with full veterancy) Cybran Commander can take on a Collosus and live. Make sure that the Collosus doesn't move, though, or else the Commander's Tac Missiles won't do any damage. Also, don't forget to overcharge the cannon, or else the DoT upgrade won't do much.
The ability for the Cybran ACU to safely destroy 100's of basic units has been attributed to a known glitch, which should be fixed in upcoming patches (PC). The issue will still exist on the 360 version until Square Enix releases a console patch.
A cheap way for this unit to gain veterancy is "The ACU rush" strategy. On maps where you and your opponents are close together, like Seton's Clutch, in the early game, let your engineers do the building and walk your ACU to your opponent's base. This will give you early research and an at-least-2-points-Veteran ACU. Upgrade and repeat to consistently harass them.