Grief is for the +340-400 damage mod. The damage is added to smite (doesn't show up on the LCS). The damage is also added to zeal (doesn't show up on the LCS as far as I know). That damage is quite impressive. It also offers ITD (which ebotd does not), which is great for patching any lack of AR you might have. I've never owned a nice ebotd zerker, so I can't compare it, but as far as killing things goes, you don't really need more than what Grief gives you. But if you like your ebotd, then go for it. It's by no means a bad weapon to have.