You essentially draw a card on attacks, but you get to cast that card for free if you built your deck with mostly odd mana value cards
Its reprint in MH3 brings it into Modern, although it's probably not going to see much Modern play except perhaps in some fringe decks
Now dont get me wrong: Im not saying you should replace Shark Typhoon with Emerias Call, but Azorius Control players will want as many wins the game without needing to be a card that wins the game cards as they can get
The new Jin-Gitaxias copies the first sorcery, instant, or artifact its controller casts each turn and counters the first sorcery, instant, or artifact that their opponents cast each turn
The deck proved to have an incredibly powerful combo with the card Scapeshift, which let a player replace all of their Lands with different ones
If your commander dies, you can pay life instead of commander tax, so recasting it isnt a big deal