By the way, 40-40-20 is no better from a control perspective than even thirds. Two can sell the other out. And control is a bigger issue than percentages in the sort of pissing contests that matter. Even worse, the person with 20% has more to gain by cutting one of the 40%'s out...as do each of the 40%'s.
Maybe in some corner case where it isn't a waste of energy? That's why it is worth at least considering Joel Spolsky's advice:
https://gist.github.com/isaacsanders/1653078
By the way, 40-40-20 is no better from a control perspective than even thirds. Two can sell the other out. And control is a bigger issue than percentages in the sort of pissing contests that matter. Even worse, the person with 20% has more to gain by cutting one of the 40%'s out...as do each of the 40%'s.