Just FYI, if you Adrenaline an Eclipsed Vampire (3/3) it attacks 4 times. Might be a little faster, since you have to accumulate the quanta for Adrenalines instead of Fractals, and you won't need so much Darkness quanta. You could incorporate things like Heals to increase EMs, or add Devourers to slow AI3s down. Dusk Mantle is one of the best shields in the game, and although you don't really need it in most AI3 matches, that too would help you on a good draw from the AI, and you'd have the quanta for it if you weren't spending it all on Minor Vamps.
Generally fractal/darkness decks start by fractaling Devourers for control and so you don't need to save up so many turns to play vampires. Upgraded, I think fractaling Devourers then Vampires is the way to go. But for unupgraded, I prefer Adrenaline in a Life/Darkness duo, myself.
The tradeoff is that killing one Andrenalined Vampire is like killing 4 played from a Fractal, so you will be more susceptible to CC. I personally think Adrenaline is the way to go, though, if you want lots of Vampirism.