I strongly recommend the Kar'Fi. Personally I use it on my KDF Sci and I wouldn't change it for anything else. That is, unless Fleet Kar'Fi will be added someday.
People are already crying that Vesta is OP, but quite frankly Kar'Fi eats it for breakfast, even without sensor analysis. Escort weapon layout, ability to mount dual cannons, two hangar bays with truly awesome Fer'Jai Frigates and quite decent boff layout.
It's not very durable, especially with only lt.eng boff, but for PvE purposes it's one of the best choices you can make atm. Really fun ship.