Originally Posted by
Cheesegear
They both mean the same thing. However, in some situations you can be removed from the board without being dealt any wounds (which is what the question is getting at) and it does get rid of those pesky Eternal Warriors which makes these things quite good; Jaws of the World Wolf, Dark Eldar Shattershards, Captain Stern and I think one of the things from Chaos Marines does it too, are just off the top of my head.
Jaws is a staple of the game now (i.e; Space Wolves are one of the best armies in the game and are everywhere). What, you don't take Allies?