This is a pretty savage case of thread-necromancy, but ah well
The problem with 017 mulligans, or "just mulligan till your hand is playable" policies it that they either reward bad deckbuilding or, even worse, hide the effects of bad deckbuilding until its too late.
A good EDH deck should play 38-42 mana sources -- the best deckbuilders I know (RobRoy, TigTigger, BKM, Dickinson) all tend to the high side. New players tend to skimp on mana though, sometimes going as low as 34-35 in an attempt to shoehorn in more fun cards. Allowing them to mulligan until they have a good starting hand is actually quite mean to these people because it appears to mitigate the problem but it just screws them in the mid and late game anyway. The mulligan lets them hit their first 2-3 land drops at pace, but then they lag behind as the game proceeds... leaving them impotent for most of the game every time, and surprised when their opponents steamroll them with more resources.
As such, I prefer to enforce regular mulliganing... the length of EDH games makes the distribution of cards far more important than the actual number you start off with.. even if you go down to 5 (which is 3! mulligans) to find a good hand, you're only down 2 cards on everyone else which is likely to be irrelevant over the course of a long game if you have a reasonable amount of mana.
Just my opinion though... how you mulligan is definately a local group kind of deal.