Wait, I missed something; which is better than the other?
Same as in D:OS EE, wands are automatically ranged weapons and let you have more bonuses given that you can hold two of them and forget they're there -> This makes wands the clear choice for a mage given how important your main stats are and how hard it is to build them up without being shafted somewhere.
EDIT: Unless, I missed something? It'd be pleasant to be wrong on this after D:OS EE making staffs moot
EDIT2: Oh, and someone brought up (on steam) how having two wands that synergize (earth/fire or water/air) can let you have combos -> Not exactly sure if this true since I never actually relied on wands/staffs in combat *shrug* except that odd bash skull with staff at beginning when not enough spells