I'd go for the Arcane Barb. With the high AS on Calamity you will deplete your hatred faster and each attack ought to do less damage due to lower damage range on Calamity. Just my opinion. I found a Calamity today and I don't even think about using it.
You'll deplete hatred faster but regain it just as much faster. Which should result in a more or less equivalent final DPS in any fight lasting longer than a single hatred bar. Which is most tough fights.