In my opinion, the Mongoose is as good as the person wielding it, regardless of who bats with it, one success will be based on ability, however I believe it is still early to say what kind of impact using it will have in the IPL, even to date, a number of players have done better than Hayden in runs scored, 4s and 6s hit, after playing the same number of matches with him! On these Indian wickets it might be the ideal tool for the trade, a true test would be on wickets in South Africa, Australia or England where balls can coming seaming at the throat or face, it would be interesting to see a defensive shot using it, as one person already alluded to.
But nice to watch in action in the hands of Hayden.