Well I pugged MH yesterday and Khazro looked a bit marginal for Mana - so I popped a gaurdian on the tank - I used it, other healer priest used it and the s/priest used it - noone blew up and the boss died.
It's pretty meh - only place I have bothered TBH, and I'm not going to bind it or anything. But hell - it's a free spell! Rotate my bar - click and off we go.
but 8 secs is just plain silly. Why give a spell that will be used in one or two fights the whole game? this thing is so situational raid only I can understand it being forgotten and unused