Sell me on: Orb of Definance
I don't really "get it". I understand that extra HP & Armor is always appreciated but what's with the 5 second invulnerability? Seems like that would just give your opponents a chance to position themselves optimally for when you return to normal not to mention a chance for them to use their consumables safely. I see a decent amount of praise for the item but never an explaination of why or how you'd use it and the once or twice I've seen it used in-game was less than impressive.
Basically, as a PUGer, why should I spend several thousand gold on this item?