First off let me apologize if this has been debated in the forums before. (Frankly, I'd be surprised if it hasn't.) I'm still fairly new to STO and have yet to learn all the mechanics of the game.
I've been debating getting the Tactical Escort Retrofit and I'd like to gather opinions on the proper weapons loadout for it. I've heard several people say that you should use 3 Dual Heavy Cannons and 1 Quantum Torpedo Launcher forward and 3 turrets in the rear. But is this really the best way? That configuration would certainly give you a lot of firepower up front, but not so much in the rear. Now, I understand that an escort will want to always "face forward" during a fight, and an escorts maneuverability will limit the time an enemy is in your rear firing arcs, but I still find this configuration limiting. Maybe it's due to my experiences with cruisers.
The reason for having 3 turrets in the rear is because they've got a 360-degree firing arc, so they'd be firing at whatever you're flying towards along with your front weapons. Combine these with Dual Heavy Cannons, since they're so power-efficient (because they have shorter firing times and longer cooldowns between being fired), and you can hit things pretty heavily, especially coming out of cloak fully buffed for a prime alpha strike. Your weapons only ever really matter when you're pointed at the enemy, so you want to be able to throw as much damage as you can forward. If an enemy is behind you, you whip around to get your cannons at them. You aren't fighting with your *** like you might in a cruiser!
The reason people recommend a torpedo launcher is because the Tactical Escort Retrofit has a lot of Tactical Boff stations, and if you aren't using torpedo abilities, you're wasting some of those Boff skill slots.
People have made all kinds of escorts run just fine with an all-energy loadout instead of torpedoes, though, so it's doable and in some cases, may be preferable. If you use your Ensign and Lieutenant slots for your cannon abilities, and then the higher ranks maneuvers or something, you could forgo the torpedo launcher. I opted for the torpedo launcher myself though, so I'm not the best to ask about an all cannon/turret loadout.
I have an MVAM Escort, the basic loadout is the same so... I use Dual Heavy Cannons x3 and one Transphasic Torpedo Launcher in the front. Those torps have less DPS than a Quantum but the shield bypass evens things out.
For the rear I have two beam arrays and a turret. The beams are for using beam skills like Target Shields. For large enemies such as the Borg Cube, the beams will skill hit the target in front of the escort as the firing arc includes the vertical range.
I've recently been playing with a tricobalt mine layer in the rear and it is FUN! Swoop in, get in the middle of a flock of enemy and drop my egg. Then swoop off while firing all weapons. Big ba-da-boom.