I used it on my past life. I didn't have much time to test it, I reincarnated about a day after I grabbed it. For my toon, it worked very well, 12/6/2 warlock/ranger/rogue. The aura gives it a charge every few seconds, and my dual wield would fill the spell power in seconds. And that's ok, because I swing insanely fast, and every strike adds 3d4 light power that scales with spell power. Extra melee doesn't hurt either. I actually like to combine this with the same concept from divine crusader.
At any rate, I'm a highly specialized build that combines magic and melee attacks to create a lethal killing frenzy. I've often used the embodiment of law, and I haven't looked at all the numbers to see how it adds up. I just think that this is better in my case. It's tough to tell, because I have so many numbers flashing when I fight. Weapon damage, sneak damage, light damage, aura damage, weapon elemental damage, consecrated ground damage, critical damage, spell critical damage. And so forth. The thing is, the straight damage on embodiment of law, doesn't add to the crit value, and I have improved crit and overwhelming crit on scimitars, and then about a 30% crit chance for light spells. The spell/melee power affects that, which is why it has better long range potential.