Eeek =.="

[Triumph]

Naturally, I'll provide the argument for hammers.

Even at level 20, the damage of the hammer is already 10-15 points higher. The efficiency of going with a hammer varies with your build. Assuming you've gone a 1:1 STR/END build, you have 25 points by level 20, and should have 12-13 points invested into strength, yielding 14 damage bonus.

So, the damage ends up being approximately 24-29 damage higher.

The mace hits at 1.1 seconds per hit, whereas the hammer is slower with a 1.3 second per hit. In an average 10 second fight against a monster, assuming you do 60 damage a hit, your results would be the following:

Mace: 540 damage.
Hammer: 672-712 damage.

Therefore, I would recommend the hammer.