Marauder Bomber
The Marauder Bomber is the Imperial Navy's primary atmospheric heavy bomber. When a target is too small or too defended to destroy from orbit, but too far behind enemy lines to be reached by infantry or artillery, the Marauders get called in. Like other Imperial Navy aircraft, they can make an attack from an orbiting mother-ship, or from ground-based airstrips if space is too dangerous or the campaign starts to run long. They can deploy in support of infantry, but are most often turned loose into enemy territory to bomb whatever targets they happen to find there.
In appearance, the Marauder is basically every World War II bomber, but IN SPACE; it mounts a twin-linked lascannon turret in the nose and twin-linked heavy bolters in the dorsal and rear turrets for self-defense. Its four massive engines and fuel tanks give it intercontinental range, and it's so big that, in the Forgeworld 7th ed update, it's a Lord of War super-heavy flyer.
The Marauder and Destroyer have the dubious distinction of being the only Imperial units unique to the Imperial Armour Aeronautica book as all the rest are available in IA 1.
At 400 pts The Marauder bomber rocks a hefty 12 heavy bombs which grant it a S6 ap4 Apocalyptic Barrage that targets the table instead of a unit. However the better choice for nearly every occasion is to take the two Hellstorm template bombs with s7 ap3. These have an unusual mechanic in that they only scatter in one dimension in line with the Warhammer Fantasy artillery pieces and also target the ground instead of a unit. As such these provide something resembling a reliable and even cost effective hard counter to invisible Seer Councils which they insta-kill, biker conclaves, and a threat to most forms of cover loving Tau.
Marauder Destroyer
The Imperial Navy developed the Destroyer variant of the Marauder during the Second War for Armageddon, as the Orks' air superiority meant that missions could only be flown at night and close to the ground. The twin-linked lascannons in the nose were replaced with six autocannons and an advanced ground-targeting system, the tail turret was equipped with twin-linked assault cannons instead of heavy bolters, and the bomb payload was reduced by half in order to gain the capacity to carry eight missiles. Though it lacked the payload to be a proper strategic bomber, the Marauder Destroyer was successful on Armageddon and elsewhere since then as a close air support bomber. It was so successful, in fact, that fluff says it is currently the Imperial Navy's primary bomber. So, basically, this variant of the vanilla Marauder has outstripped its parent design.
On the table these are a mixed bag. Despite being the only Imperial vehicle, and quite possibly the only vehicle in the game, which can shoot 13 different targets in the same shooting phase on top of a modestly powerful bombing run, with A11 all round you're paying a rather absurd 505 points for something that has all the survivability of 3 flying Rhinos. The strafing run USR means it's going to chew up anything susceptible to Autocannons, but that doesn't really encompass serious threats. The Hellstrike missiles suffer the same problem, being one shot krak missiles with the ordnance USR making them only arguably useful in the av12-13 space, and a waste of points vs av 14.
Whilst they can make a reliable dent in nearly anything, it's *just* a dent since Hellstrike missiles can never score explode results outsides of open topped vehicles. Against monstrous and gargantuan creatures these start to show some promise but are categorically outperformed by equivalent points (and $) in all-missile Vultures. If deployed in games where target saturation, i.e. actual walls of rhinos/buggies/chimeras/3+ save MCs make up for the qualitative short comings, a Marauder will shine but otherwise it's for Apocalypse only.
Marauder Vigilant
Only produced for Forge World's Aeronautica Imperialis game, the Marauder Vigilant is a command and control aircraft that replaces the dorsal turret and bomb bay with advanced surveillance and control systems while also switching the lascannons with heavy bolters.
Marauder Colossus
Another Aeronautica Imperialis-only variant, the Marauder Colossus loses the dorsal turret to accommodate the massive Colossus bunker-busting melta bomb.