from me(68 warlcok) to u:
sincerely i do not EVER recommend using it, unless for the sakes of ********* and giggles of killing a party member, and the times you will need to do curse of doom for it to pop, is the same times you will cry when you see it break enslave at 3 mins(with improved enslave) or 0.000005 seconds with normal enslave and he kicks your ***, his damage is nice, he looks insanely cool, but the breakup is not nice at all,and he has a lot of hp, to like solo kill him without wasting hp and mana, to above poster and OP too, he is NOT elite, even if he breaks, but he looks like one, with all the stats and dmg, mainly when you do curse of doom in instances or solo you do NOT want him to get summoned, you want the curse to do a LOT of damage, and it is very nice, when i was level 60(the good ol tiems in MC) 5 warlocks including me in MC would dot main giant, while doing CoD on offgiant, while a 6th did improved curse of shadow, most of us were affliction, so we did amplify curse too.
believe me, seeing the giant lose 50% hp after 1 minute was EXTREMELY fun.