The Maxim is a rapid-fire, extra-long-range (three kilometers!) anti-hull cannon. It is clearly designed for the purpose of making capital ships' lives miserable, allowing the player to destroy subsystems and even whole smaller capships with ease from beyond the range of return fire. It does produce some "shake" effect as it fires, degrading its accuracy somewhat, but if you fly in third person mode, your screen doesn't shake. Because of its high rate of fire, despite its low shield damage it is also still mildly effective against shielded targets. Be aware though that this weapon is perhaps the biggest energy hog of them all, and will run you dry with mere seconds of sustained fire.
Despite its range and high rate of fire, the Maxim is a mediocre bomb interception weapon. It has high recoil and uses a massive amount of power. The best bomb interception weapon is the Morning Star, with this or the Mekhu in second place.
The Maxim is a very convenient weapon if you know when and where to use them. By default, the Maxim is a good weapon to take down subsystems—especially larger turrets—and weaker cruisers from a safe distance. Remember it devours a lot of energy, so I suggest you keep your recharge rate maximum while firing, unless you are in a hurry to approach your target. The "shake" effect does not affect your accuracy if you do not steer your ship; however, it will be distracting during a dogfight. If you are expecting a hard dogfight, either take "Dogfight Primary" + Trebuchets or Maxim + lots of "Dogfight Missiles."
This weapon is of little use against Shivan fighters, as they have strong shields and hulls so weak, that you can destroy them with a few hits from anything. Larger ships, or even heavy bombers, are different thing, however.
If you're expecting to see some warships jump into your operations area, and you have access to this weapon, it's definitely worth a look. Using a Maxim cannon, you may be able to disable at least some of a warship's armaments before it gets anywhere close.
The classic combination of the Circe and the Maxim are excellent against Shivan fighters and bombers when fired in short bursts. They both use up so much energy that it's hard to keep a steady stream of fire. The long range and the high hull damage of the Maxim is excellent against anything that's slow and unshielded.
Capable of bomb interception, cruiser killing, subsystem disabling, and fighter/bomber killing (when paired with the Kayser or Circe), the Maxim is one of the best weapons in the game, aside from the high energy usage of almost all late-FS2 guns.
You can circumvent the shudder effect almost completely by switching to 3rd person view (the * key on the numpad) when firing it.
The Maxim is described in the techroom and when first introduced by Admiral Khafre (of the GVD Psamtik as "by definition an energy weapon, though it behaves like a high-velocity mass-driver cannon"; this appears to be the result of some confusion on the part of whoever wrote the description, as the Maxim behaves like an energy weapon (shooting glowy blue projectiles and eating through your ship's energy) but is by definition a mass driver (it accelerates uranium slugs, after all).
The Maxim also has tremendous potential for cost-effective and potent ship-killing and disabling when used in place of bombs. Here are some basic calculations on the damage output:
Range: 3.5 km
Base/armor damage: 26
RoF: 6.67 /sec
- 2: 346.84 /sec
- 4: 693.68 /sec
- 8: 1387.36 /sec
- 12: 2081.04 /sec
- 16: 2774.4 /sec
- 18: 3121.56 /sec
- 20: 3468.4 /sec
For reference, the massive Helios bombs do about 6800 damage each, but are vastly more difficult and costly to deploy (limited range, long lock-on time, slow and large projectile--meaning easy to intercept, and few platforms capable of launching them in the first place (basically only heavier bombers)). Eight Maxim cannons could do as much damage as one Helios warhead in about 5-6 seconds...from a range of 3.5 kilometers, with no possibility of it being intercepted. A heavy strike craft designed around this concept could vastly outperform even Ursa bombers fitted with Helios bombs with only a fraction of the risk and cost, as well as being more time- and resource-efficient. Mount 4 of these on an Ares and you can dish out 693 damage per second from 3.5 kilometers away, while still being free to use loads of Trebuchets or Tornadoes for anything else you want. An Ares could even mount 6 of them at once.
There are, however, two limitations to this: energy usage and lack of effectiveness against shields. The former means that even a medium bomber would not be able to sustain fire with 8 or more Maxim cannons for that long, though this could be plausibly addressed by a new/modified design that replaces larger secondary capacity for more power generation. The latter means that any heavy strike craft fitted with only Maxims would be rather reliant on an escort more suited for anti-fighter roles. That said, 8 Maxims can still effectively take on shielded craft with a sustained burst.