And I'll tell you that - despite having nearly the same setup and equipment on my fed sci flying a tactical vesta with 4 phaser relays I still cannot deal the same amount of damage I usually do with the kdf sci on Kar'Fi. I don't know why is that, honestly, as the only major difference is the Plasmonic Leech console, another hangar and bio-neural torpedo I use in the 4th fore slot. And the only major downside on Kar'Fi's part is slower turn rate and lack of sensor analysis, really.
On the Vesta, if you throw everything into Aux like most, you'll starve the rear turrets during CSV and CRF, which has a larger impact on DPS than most people probably think. On the Kar'fi if you're running the KHG 2-piece set, particularly with the engines, on top of the Plasmonic Leech, you'll have respectable Aux levels even with full power to weapons. Plus, the Kar'fi can shoot out pets a lot faster from it's dual hangars, and the frigates are very nice damage dealers.