Quick answer :
Without Dark Soul, it is crappy.
In single target, it is only a DPS gain if you risk having fury left when DS fades.
In AoE situations, if you want to maximize your DPS on the boss, HoG is much better.
Otherwise, it is great for burst but weaker than HoG on sustained AoE situations, mainly because HoG gives you MC procs for each target hit.
The only situation where it is far superior to HoG is during Execute Phase, because in this case you do not care about the extra MC procs.