This is another "it all depends" situation. I'm not going to board a high level flag ship and pull out the doll unless I plan on doing the chicken run. It's Flame or Wither all the way for that scenario. However, after getting pummeled and losing health you bet I'm switching to doll to chain n drain and probably start the chicken run anyway. This is typically when I'm alone or the crew have all been wiped out with 30+ lvl soldiers on board.
I'd have to say I use both the staff and doll equally. You cannot heal with the staff, but you can't do major devastation in a short time frame with the doll. Sure you can attune up to 5 enemies....but by the time you do that you've already taken a beating.
Indisputable (only covering what I use most):
Staff
-Soul Flay works decent when you are low on voodoo
-Pestilence not too shabby (does not use much voodoo)
-Wither rocks
-Flame kicks major booty
-Desolation...lets not go there in this thread as I have mixed feelings
Doll
-Poke not much damage but does not use much voodoo and recharges quickly
-Swarm does nice damage
-Heal is very useful
-Chains come in handy when running away or needing to distance yourself
-Life drain rocks (literally takes enemies health and transfers to your health)