I have flown complete torp boats for the last 24-mos...
I have found the Intrepid to be the most effective torp boat. Nothing against escorts but escorts are much more effective with energy based weaponry.
Now for the torp boat to be effective you must have the ability to do damage between cooldowns. That is why a sci vessel is the better choice. A tac captain in a sci ship can bring a glove to the hand and increase the DPS output of a sci ship expontentially.
Forward 3 weapon slots: Breen Cluster Bomb, Harpeng, and torp of your choice.
Aft Weapon slots: Breen Cluster Bomb, Torp of you choice, Borg Kinetic Cutting Beam
At first you fire torp spread 2 as the three forward weapons fire you notice all three are on different cooldowns. Depending on your pushers [I prefer transphasic] you can enhance the damage of at least 2 if not all three weapons if you run the rapid reload transphasic torp.
Now the sauce for the goose....
Using jam sensors 1 allows you to gain about 2-3 seconds of cooldown without being fired upon. Using Viral Matrix along with Gravity Well slows and placates a enemy allowing a second strike. Next use scramble sensors to gain another precious few seconds of not being fired upon. Depending upon which consoles you have you can then do something unexpected like using a theta radiation console or subspace jump. The idea is to use the speed of the ship to stay just outside the arc of enemies using cannons as thier primary weapons. For beam boats fly in close and use a photonic shockwave while making a bombing run.
The idea behind the bombing run is that your forward weapons have launched and you go directly at the opponent. That way when you pass the opponent you aft weapons are readly to launch. Having the right doffs is critical for timing a bombing run to get the most out of it. So unless your opponet has shot down your torps he will have a second wave hit him at point blank range. This is why you need to run full engine power.
Also this ship is quite effective in stfs. When the Borg want to use the tachyon beams enmasse to take you down simply activate your ablative armor console that comes with the ship. Sure you have no shields for a few seconds but it makes the Borg expend thier attack on you rather than your teammates. When the console power is done your shileds return at 100%. Meanwhile since you are a torp boat your weaponry is unaffected by the use of this console.
Hopefully this will give you a couple of ideas to play around with when deciding which ship works best for you.