How good is greenmist really?

[ya.dingus]

I know, it's a good weapon, but I'm not even talking about the ratios and stats, I'm talking strictly about its proc.

I've heard you can weapon swap on procs and basically double dip with your 2h epic for the lifetap dot.

Is this really that good to be picking iksar over say troll or ogre?

Also, do the other races have things that compensate race wise or is it all just flavor at that point?