From Supreme Commander Wiki
Cruisers are a class of Tech 2 naval vessels. They are very flexible units with direct fire weapons, anti-air weapons, and tactical missile defenses. The Cybran version even has air support capabilities. However, Cruisers suffer from an extremely low HP compared to Destroyers, which renders them not cost effective against large numbers of air units (especially gunships and some strategic bombers), which can sink them before they get a chance to inflict enough damage. Cruisers are not particularly powerful naval units and will generally lose battles against other naval units, but they are a very useful addition to any naval group. Cruisers have higher energy costs than Destroyers but lower mass costs and build times.
[edit] Factional Differences
The UEF Governor Class and the Seraphim Ithalua are somewhat similar, being both equipped with Tactical Missile Launchers, the Governor Class firing rapid barrages every 10 seconds while the Ithalua fires a constant stream of missiles. The Governor Class has the weakest AA capabilities of the 4 Cruisers, while the Ithalua has the stongest and is also the only one equipped with Flak, giving it a considerable edge against swarms of gunships. The Governor Class has poor direct fire naval capabilities, while the Ithalua has none at all. The Cybran Siren Class has the second weakest AA capabilities but also has by far the strongest direct fire naval capabilities, making it efficient at shore bombardment and even allowing it to fight directly against other naval surface units. It also has a landing pad on the back deck, allowing it to refuel and repair patrolling aircraft in the field, an ability not to be underestimated. The Aeon Infinity Class is the toughest Cruiser and has extremely good AA as well as a reasonably good Quantum Cannon mounted on it, but is the least flexible of the four, not possessing tactical missiles like the UEF Cruiser and the Cybran Cruiser, nor the air-staging and anti-missile capabilities of the Cybran Cruiser. Due to the Anti-Air weapons that the cruisers are armed with, the Aeon Cruiser is far superior to the others at destroying T3 Aircraft, not purely based upon DPS, but on Effective DPS, as the SAM Missiles track - allowing them to actually hit a fast moving T3 air unit. The UEF Cruiser is similarly armed, but with far lower DPS, whereas the other two are not - making them most effective at taking down T1 and T2 aircraft.