So I've actually got the myrmidion helm http://www.wowhead.com/?item=28180 from the quest, the greathelm of the unbreakable http://www.wowhead.com/?item=27520 and was able to pick up the felsteel helm in the AH for a whopping 15g http://www.wowhead.com/?item=23519
So the question is, which is better to tank with? TO my untrained eye, I'd go with the felsteel helm even though I'd be losing a fair chunk of stamina I do gain 3 slots that could be turned into stamina slots, or for me who needs more defense ratings thats probably what they'll be used for.
Please steer me in the right direction if I'm completely off in left field