The Catalyst Navy Issue is a potent upgrade from the stock Catalyst. Sporting an extra mid slot, superior damage and better tank, the Catalyst Navy Issue excels at engaging smaller vessels.
The Catalyst Navy Issue can be flown in a similar way to its T1 relative, using blasters to achieve extremely high DPS that can cut through active tanked frigates and destroyers. With the extra range control afforded from its third mid slot, a Catalyst NI pilot can make up for the difference in speed between it and the other small ships.
However, the additional ability to dictate range opens up another possibility: fitting the Catalyst NI with railguns to scram-kite its opponents. Such a fit could spell doom for scram-kiting frigates and even some of the shorter-ranged kiters, as the Catalyst can still maintain high DPS while hitting out to nearly 20km falloff. Watch out for high-speed brawlers like the Dramiel, which could potentially close range quickly enough to get under your railguns.