I saw some matches when batsmen were using Mongoose bats, but why don't they use them in One Day Internationals and Test matches? What difference does it make in cricket?
As stated on the Mongoose website:
We believe that when a ball gets hit, it should stay hit. That’s why we design our bats with two principal advantages over anything else in cricket: faster bat speed and bigger sweet spots.
The bat’s extra power comes from increased rigidity in the blade and increased flexibility in the handle – so you can hit further and harder. Its blade is 33 per cent shorter than a conventional bat and the handle is 43 per cent longer. This allows increased leverage that makes the bat quicker and easier to manoeuvre, allowing you to select your shot later, or change it in a split second.
Bats are like a see-saw, and the MMi3, as it has a) a longer handle b) a shorter blade c) lighter as a result of a and b, means the fulcrum is moved further away from the batsman, meaning that he does not have to make as much effort to hit the ball, or the ball will go further with the same amount of power, meaning more sixes, and with T20 being the shortest form of official cricket, sixes are integral to posting an unchasable total.
The reason it is not used in other forms of test cricket is that it is terrible as a defensive bat. It can only really be used to slog. In test cricket, you attempt to bat as long as possible, and can you imagine trying to defend a ball that spits out of the rough with men around the batsmen? There is more chance of it hitting the handle, where you have no control on the shot. ODI cricket, while you are trying to score quickly, you also put a price on your wicket and is a balance between test and T20. 50 overs is a lot longer than you may think and if you want to have a chance you need to bat out your overs. It would be silly to use a mongoose other than the final 5 or so overs.