Use Beast as a secondary wep. It has fanat aura which gives more damage. I prefer grief because it deals a significantly higher average damage than EBotDz and it has -25% to targets defense which helps a lot.
Grief is amazing sustained damage. Having one grief will always guarantee you hit pretty high consistently. Combined with a beast, its even better. Using two griefs isn't as good as a beast+grief combo though. I hope this helps
Depends whether you are pvm or pvp. The worst grief will still outdamage a perfect eBotdZ, and for pvp it's grief hands-down. Botd shines more at pvm, with high leech and indestructibility but lower damage.
For pvp it's grief
For pvm it boils down to whether you like faster damage and don't mind repairing or you like high leech and no repairs ;D