Generally, I open a trash pull with an Unleash or two, put a couple of enmity-generating hits on everything, then Blood Price if it's up, and rotate through targets hitting things and checking none of them are at risk of getting loose.

On bosses, I start with Plunge or Unmend, turn the boss away from the party, then throw a couple of Dark Arts-Power Slash combo finishers and then switch to DPS combos until someone starts getting a little higher on the threat meter than I like.

Unleash is very good, but make sure you are going to have mana for it, and make sure Provoke is cross-classed where you can get to it easily.

In group pulls, especially large ones, it's more than worth the mana hit for Dark Arts-Abyssal Drain.