If you hit one Vampire with all your buffs, or even 3 or 4 of them, TU is effectively doubling what those cards do for you. I would go with those personally, but if you want to spam Vampires then that Fractal works too. I just like TU better because I think the buffed vampire is more fun than spamming regular ones, plus the fact that you only need 3 Supernova to play it instead of needing 4 of them makes me think adding 2 TU would be better. You could probably afford to cut out a Chaos Power (or Obsidian Tower- not sure how needed all of those that you have are, especially if you don't carry Fractal anymore) in order to keep it to a 30 card deck.