From Supreme Commander Wiki
The Tech 3 Air Superiority Fighters (often abbreviated as ASFs) are the most powerful fighters that you can build in the game. They have enough power to be a highly mobile defense force capable of taking out even experimental units, at a (relatively) affordable cost. However, these units have a somewhat hard time targeting slower units (with the exception of the Gemini, which has missile systems), and can be taken down by the Restorer easily. That said, these units are effective in many situations and can be a tremendous help to any commander in need of defending against air attacks.
[edit] Factional Differences
The Cybran Gemini has missiles, as opposed to the plain direct fire weapon mounted on the other ASFs. This results in less shots missed and leads to a higher Effective DPS.
Although it may look like the Aeon and Seraphim ASF's have much greater DPS than the other factions (405 DPS vs 200 DPS), the Cybran and UEF ASF's have two 200 DPS weapons, making for an almost exact match in DPS (405 DPS vs 400 DPS), besides the Cybran ASF weapons being missile launchers.
The UEF ASF has the most health, and the Cybran ASF has the least health. The UEF ASF also has the highest initial shot damage of all the factions. This is balanced out by the slightly slower rate of fire. This is only significant when taking on slow or stationary targets, as this will occasionally allow one to take out the target in a single pass, when a fighter with lower initial shot damage would not have done so - making it open for return fire.
The biggest difference is that the Cybran Gemini is equipped with stealth. This alone makes it the best ASF, as other fighters cannot shoot at it when it is outside visual range, unless it is in range of an omni radar system.
The four Air-Superiority Fighters. From left to right: Cybran, Aeon, UEF, Seraphim.
