The Titan Assault Bot is a UEF land bot. It has considerable speed and upgradeable anti-air. It fires gauss-accelerated projectiles out of each arm-cannon. It is lightly armored but does relatively high amounts of damage, and should be mixed in with Rock Heads to soak up fire.
Large groups of Titans can easily knock out a forward base or an army. With the Noah Unit Cannon it can easily cause havoc and mayhem in the enemy base.
Keep them on the move using them as quick strike squads that do damage as they pass. If they can run deep into the base they can kill important buildings before they die.
Keep in mind that the only constant advantage Titans have over the Rock Head tank is the increased speed, therefore the Titans can make a good "hit & run" tactic and are better used in waves in the early game than the Rock Head.
Although useful in the early game, they aren't affected by the "Stacked Gauss Cannon" upgrade, meaning Rock Head tanks do equal DPS (75) to the Titan, but have more health and superior range on their Gauss Cannons. Additionally, the Titan's Flayer AA guns do more damage, equal to the Archanist for only a slightly higher cost.
Like the Rock Head, the Titan uses a Flayer AA missile launcher to target air units, meaning it can still hit a target as the missiles continue tracking, even outside their maximum range.
In the DLC Infinite War Pack One, there is a research option, the Afterburn that unlocks a speed boost for all land units for a short amount of time. This causes Titans to move extremely quickly, and makes them very effective at hunting down a target.
In Supreme Commander it first starting as heavy tech III assault bot, which used plasma weaponry and started with shields, and was accessed by the land factory being upgraded to tech III. It also had a tactical missile launcher, deeming it one of the most powerful land units in the game.
In Forged Alliance, it got a faster firing rate, more health, and lost the launcher. The Percival took over its assault role because it had the more powerful plasma rifle, was amphibious, and had 8 times the health. However, the Titan still kept it's hit-and-run role due to its speed and fire rate.
In Supreme Commander 2 the Titan has been diversified, having unlockable AA, shields, health, damage, etc. It keeps its hit and run role from FA, as the Rock Head is better suited for assault, since the Titan's health went down from 1200 to 1100, and its shield is one tenth of the capacity it had in Supreme Commander.