From Supreme Commander Wiki
The Tech 1 attack bomber is an early game air unit that drops small bombs on ground and surface units. They are generally fast, though not as fast as Interceptors, and have light armor. They have no anti-air capabilities.
Bombers are vulnerable to Interceptors and anti-air defenses.
Despite these drawbacks, attack bombers make excellent tools for use in early game, capable of performing base defense against small bands of T1 and sometimes T2 units, as well as providing an early first-strike capability against an enemy base or outlying mass extractor. Do not, however, overestimate their potential and send less than 6 against any position defended by any sort of AA, or you may come up short in your goal. If possible, escorting them with Interceptors is a must.
[edit] Factional Differences
The Scorcher drops 5 napalm bombs with moderate blast damage and good damage over time, a good asset against early game swarms of light assault bots.
[edit] Cybran
The Zeus drops 6 Neutron bombs with a large blast and high damage. This is most effective against large groups of foes.
The Shimmer drops a single, large energy bomb with a large blast radius, as well as the side effect of temporarily paralyzing and disabling units caught within. This ability makes it perhaps the best T1 attack bomber, as that small delay gives other support units time to get in free hits.
[edit] Seraphim
The Sinnve utilizes the Othe Tactical Bomb, a miniature version of the one used on the Ahwassa Experimental Bomber. This Bomb deals 250 damage, making it the most damaging, as well as combining this damage with the high blast radius of the Shimmer. It, however, lacks the paralysis effect of the Shimmer's Graviton Bomb. The Sinnve, as well as the Shimmer are best suited for the bombardment of outposts and bases, due to the more concentrated damage which is more effective in the destruction of buildings.
At least with the Zeus, T1 bombers are more effective when out of fuel, since their extremely low airspeed makes it possible for them to have a "drop window" long enough to drop two sets of bombs. This, however, makes them even more vulnerable to anti-air, so use accordingly.