Must i note, all these hullbasher weapons (razors and mortairs) are powerful no doubth. But its when you have energy. In any case you will run out of energy only by firing both cruiser or destroyer turrets. If you have razors, then yes, its a good way to deal quick damage in short while, but what if you miss? 1/4th of your power is gone and while constantly firing, it wont regen as fast. So stick with the turrets only loadout.
As for energy effic. The cruiser turrets reload faster though are weaker, but if you multiply the shots per second and the damage, they are still more powerful than the destroyer turrets. Not to mention, oddly, more energy efficient.