Quote from blujay
Life Steal can hit multiple targets. If you have 6% and you're an AOE caster it's not bad.
Life steal only has 20% effectiveness in inferno. If you have 6%, you actually only have 1.2%. It will eventually outscale life on hit, but currently it isn't very good at all. Perhaps after the IAS nerf life on hit won't be as amazing as it is. We'll just have to wait and see.