I say the Angel of Destiny. The Avatars could only work with the Charmed One's assistance. Angel of Death can only take souls after they have passed on. And finally, The Elders mainly contain what is there. The Angel of Destiny has the power to take and give back.

Your discussion is fair but...

The Angel of Death is someone who is neutral, when I saw him working with the Charmed Ones and also with the Demons, I just remained astonished. He is one of the best beings that was on Charmed.

I just can't stand the Elders nor the Avatars, and for the rest I agree with Sephora

He does what he has to do and gets out, unfair as it may be. He's a straight to business kind of guy. Then again, the Angel of Destiny possesses the same qualities, but the Angel of Death creates balance - death is inevitable, whereas destiny is never for sure.

Destiny seems neutral as well. Didn't you see where she gives Leo back, and also where she tells Billie that she will reunite with her sister again? Good and bad, a.k.a. neutral. At least that's how I see it. Two neutrals to two no neutrals.

and the angel of death, i agree with ^^^ also the angel of death warns piper about leo which is nice