The above poster is right on - the mobs just dont live long enough often times for demo lock to get all spells off when all cd are aligned. Very common in alot of situations in the game weather your raiding or grinding heroics. Very situational spec at the moment. Also has poor single target burst for nuking down trash mobs or adds. Very good single target boss dps with doomguard off cd. love spec on one fight and hate it the next