When I flew a zoner destroyer on aki (my order pilot), I found that I was -much- more effective in pvp combat using all order cruiser turrets than I was when I had a mix of various weapons like the mortar, cerberus, missiles, or infernos.
Basically, right now, 'special' capship weapons (cerbs, mortars, razors, infernos, etc.) are pure crap in pvp. The damage to energy ratio is absolutely horrid and those weapons are -much- harder to aim with due to generally low travel speeds.
Here, ill crunch some numbers to explain a little further:
Order Cruiser Turret
Hull Damage: 1,790
Shield Damage: 895
Energy Use: 8,000
Refire Rate: 2.0 (two shots per second)
That means that the order cruiser turret on constant fire does 3,580 hull damage per second, and 1,790 shield damage per second, for a cost of 16,000 energy per second. That gives the order cruiser turret a damage-to-energy ratio of 0.22375
Light Mortar (cruiser-grade mortar)
Hull Damage: 46,000
Shield Damage: 23,000
Energy Use: 500,000
Refire Rate: 0.25 (one shot every four seconds if your energy regen is good enough)
That gives the light mortar 11,500 hull damage per second and 5,750 shield damage per second, for a cost of 125,000 energy per second. That gives the light mortar a damage-to-energy ratio of 0.092, which makes the standard order cruiser turret about 243% more efficient than the mortar, easier to aim with, and much more effective against smaller ships than the light mortar is.
now, compare the supernova:
Supernova Antimatter Cannon
Hull Damage: 132,000
Shield Damage: 66,000
Energy Use: 38,000
Refire Rate: 0.17 (one shot every 10.2 seconds if your energy regen is good enough)
Hull damage per second for the SNAC is 12,941, shield damage per second is 6,470 - more DPS than the light mortar is capable of - while it only takes 3,725 energy per second. That gives the SNAC a damage-to-energy ratio of 3.473, higher than any other weapon in the game by more than a hundred percent.