Vorlon fighters benefit from a very powerful gun (probably the best fighter armament in the game). The trick is getting them near enough to the enemy to actually shoot it without them getting shot, e-mined or dogfighted to death - this is usually quite a feat.
Vorlon fighter armament is AP, AF and Beam - the trick to using them is to deploy (and keep) them no more than 1 inch from your ships (sit them on the base, basically), as anyone who attempts to dogfight with them will be subject to a charged energy pulse from the Vorlon ship before they even get a chance to dogfight. Anyone who comes within range of your ship (I'm looking at you, Thunderbolts) should be in range for fire from the Vorlon fighters, which should kill them as they get no dodge.
Shadow fighters benefit from the deployment tube on the Shadow Ship (basically fires them into combat from 30 inches away). They also have quite a tasty gun (DD on fighters is nothing to sniff at).