would you prefer higher dmg with low ele or low dmg with huge or tri ele dmg on it? Assuming same linkeds?
A bow with tri-ele dmg or high phys dmg with conversion to ele dmg - e.g. by quiver.
Blood magic pasive vs gem?
This is highly discussed topic. I still believe that none is best regarding survivability.
BM node gives you extra socket for dmg but will take from you around 400 life (3 auras)
Would you prefer low dmg (-1 socket for bm gem) and +400 life?
You can run 6 auras. Get blood magic from item (no +cost overhead). Equip -> cast mana reserved auras. Equip your usual item. Cast mana percentage reserved auras.
I'm currently quite against to spec into BM - playing HC. Thou I acknowledge it's absolutely legitimate style to play - just play style is little bit different.