Seems to be a bit controversy by all classes of tanks as to which is actually better. Pre and post Flask of steelskin's buff. I'm hearing that a battle elixir of mastery and guardian elixir of prismatic elixir is still better than stoneskin most of the time.
http://us.battle.net/wow/en/forum/topic/2325033748?page=2What I'd like to see are numbers showing the increase percentage in magic resistance/damage mitigation versus getting 5-10k more health like you do with steelskin.
Elixir of the master:
http://www.wowhead.com/spell=80497/elixir-of-the-masterPrismatic Elixir:
http://www.wowhead.com/item=58143
