The Maxim is a brand new design; a long-range, high velocity particle accelerator cannon that functions more or less like a mass driver. The weapon has the best range of any primary gun, at 3.5km, and also inflicts the highest degree of hull damage.
A tactically invaluable weapon since it outranges any existing anti-fighter defenses, the Maxim's primary disadvantages are first that it draws an amazingly amount of power to operate; and second that it causes a substantial amount of recoil. It's also somewhat difficult to score long-range hits on small targets simply due to the limitations of fighter maneuvering thrusters
If you're expecting to see some warships jump into your operations area, and you have access to this weapon, it's definetely 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.