I have a Joined Trill KDF Tac in the Krenn Temporal Destroyer. I don't play him often so I have not fine tuned him over time. I prefer to play & invest resources in my main Fed instead. But here is the build I have. I'd like to see what others have come up with also.
Fore: X4 Advanced Fleet Antiproton Dual Heavy Cannons Mk XII [Dmg]x3 [ACC]
I also have the fleet CrtD which does give a +50% bonus to crit damage but apparently Acc is best for PVP. I also have a set of XI that I purchased from the Exchange and suffice it to say, its cheaper to buy them from the Fleet store. The same goes for any other energy type.
Aft: X2 Advanced Fleet Antiproton Turret Mk XII [Dmg]x3 [Acc]
Borg Cutting beam
Borg Set XI - always has done the trick for me.
Universal LT (Science)
Hazard Emitters 1
Science Team 2
Tactical Team 1
Attack Pattern Beta 1
Attack Pattern Omega 2
Cannon Rapid Fire 3
Attack Pattern Delta 1 (I have a purple Doff that increases this but to be honest, am not convinced by it just yet...)
Emergency Power to Weapons 1 (although shields is also a good idea....)
Sub-Space Field Modulator
Batteries of some sort (i.e. Weapon/Engines/Your choice)
Make sure that you RESPEC properly via the STO planner and also go over the Hilbert Guide. Both provide excellent sources of info that will allow you to maximize your DPS output whilst also increasing survivability. Your doffs should complement whatever you build.
Longevity wise it takes pretty much an all out assault from every PVP player to take me out at this point (i.e. 4-5 ships at once) bar of course the infamous Bug ship... that thing sneezes on me and I am dead... lol.
"The world ain't all sunshine and rainbows. It's a very mean and nasty place and I don't care how tough you are it will beat you to your knees and keep you there permanently if you let it. You, me, or nobody is gonna hit as hard as life. But it ain't about how hard ya hit. It's about how hard you can get hit and keep moving forward." - Rocky Balboa (2006)