Right, I can't give you an end-all answer to that. Opinions are divided, and both camps have valid arguments, so here goes.
In my opinion, the glyph wins out over the skeleton key, but let me give you some arguments for both and you decide which one fits your style better.
Armor makes you easier to heal and makes your blocks more potent.
The avoidance use effect is highly useful in certain fights.
The badges for purchasing it are plentiful, and it's easily one of the best tanking items you can buy for those badges.
Gives you more EH then the glyph.
Stamina works versus all damage, not just against most damage.
The badges for purchasing it are scarce to say the least, and there are a ton of other good options available.
Originally Posted by Kahmal
...there is no true progression for a casual anymore, just hand outs.