Ground slam or Spectral throw

First off I'm pretty new so forgive any retarded question that I ask.

If you start from the marauder passive and you are using a 2h mace what is the benefit of going spectral throw vs ground slam? It seems like GS does more damage than spectral throw unless I'm reading something wrong. Also GS does 80% weapon damage while spectral does 60% base damage?

Spectral throw returns to the user, striking an additional time ;b

Dates dude... That post is 2 years old