T2 Gunships are air units which make use of air-to-ground weaponry to provide support for an army or raid an opponent's undefended mass extractors. Gunships can also be used to perform a direct frontal assault on enemy bases, but this is generally a bad idea as Flak Artillery and air-based anti-air solutions are extremely effective at destroying them.
The Stinger utilizes a Hells Fury Riot Gun and features a transport clamp (which can carry a single tech 1 or tech 2 unit). This allows it to carry a Mech Marine for increased DPS or a Sky Boxer to provide on-demand anti-air. It can also be used to ferry an army across obstructing bodies of water in-situ. It also features the highest armor level of any T2 gunship.
The Renegade has the weakest armor of all of the gunships, however it is equipped with an Iridium Rocket Pack capable of dealing larger amounts of area damage, making it perfect for attacking clusters of units and shield-less bases.
The Vulthoo has the second highest armor of all gunships. It's weapon characteristics are similar to the Aeon's and thus has similar applications. Since the Seraphim lack a T3 Gunship, this ship is essential even into tech 3.
However, since it has no transport clamp, equal DPS, and less health, the Vulthoo is, like the Aeon T1 Attack Submarine, weaker but just as expensive as it's UEF counterpart.