Lottery, there are some people that have had them last for ages and a lot of people, that have had them last for a short space of time.

I've smashed loads of them, never at launch, so thats a common misconception that people make, although launching it may contribute to wear it matters more higher up the rev range when your boosting it, in higher gears at max torque. Bottom line is even if you don't launch it, there's no guarantees it won't break.

Also just to add I have never broken a front diff, from reading feedback on the escos forum it appears they are substantially more reliable than is made out to be. Again, not saying it is bullet proof, but the box is way more likely to go bang first.

Since I have done a bit of research into the boxes I shall share what I have found as the fault cause. Basically the MT75 box/bearings are susceptible to wear, and what happens is that over time this creates movement of the shafts in the box, given that helical gears create a thrust force, i.e. naturally push apart from each other when engaged, then this is essentially what destroys the gearbox. With a straight cut gear you don't generate the same axial loads and therefore (theoretically) it is less likely to fail. Principle is the same for most boxes, the gears only break becasue the bearings fail or parts are worn, the broken gears are just a result of the play in the box.

Also compare this to a turbo, when you destroy this, it's not usually anything but the fact the bearing is shot and it has contacted the inside of the housing becuse of the excessive movement of the shaft