These things take a tremendous amount of space to fight, do not risk fighting them near other groups. The main problem with these is that they A) do a ton of damage, around 500dps to plate and B) wipe aggro on everyone near them. This means that there is a very high risk of the zerker wiping threat, jaunting off to kill a mage, and then being taunted. Eliminating deaths on these things is tough.