as regards to the OP its pretty useless for a raid but better than nothing i guess, if it gives you a litle extra dps thats better than nothing... just.
The trouble is it either dies in a nano second from ae damage or doesnt hit the mobs most of the time if they con orange so its not syphoning any hate. Sometimes it just sits there looking at you so dunno why that happens. Maybe it needs feeding!
I certainly wouldnt count on it for deaggro. if you're getting aggro a lot then kick the tank up the ass.
Use it to get an extra 1dps from the fight but dont expect to drop off the hate list
