[FastJack]

For the times when the dice pool is small (6 dice or less) adding the Edge dice to the roll can give two or three more hits, with the potential for more hits than the dice pool could generate on its own (keep rolling those 6's).  When it gets into the double digits, it starts getting more efficient to buy the reroll.

Are we 3:rd edition? ´Cause I was thinking 4:th here, where 5 and 6 are equal successes and the sixes don´t explode?

Also, you never get to spend more than one point of Edge per roll, right? Can´t keep spending to reach even better result..?

Actually, if you spend Edge on the roll before you start rolling, the sixes explode. A nice side effect for adding your Edge dice.

[Nomad Zophiel]

Someone should really sit down and work out the mathematically optimum choices for Edge use at various dice pools. 

[Dead Monky]

Don't encourage them.

[Chaemera]

Yeah, don't encourage me. I can't check the books at work & have too little time at home.

[The_Gun_Nut]

Sixes explode with Edge spent on extra dice.  Spent beforehand they ALL explode.  Spent after only the Edge dice explode.  If you have a large dice pool then you get more bang for your Edge buck by purchasing the reroll; you get another chance for 5's and 6's to hit instead of just 6's.

[Chaemera]

Sixes explode with Edge spent on extra dice.  Spent beforehand they ALL explode.  Spent after only the Edge dice explode.  If you have a large dice pool then you get more bang for your Edge buck by purchasing the reroll; you get another chance for 5's and 6's to hit instead of just 6's.

First, only dice that didn't score a hit (4 or lower) are rerolled.
Second, Rule of Six only applies when you spend edge to add dice (all dice, if spent before, edge dice only if spent after rolling).

Read the Spending Edge section, the Rule of Six is explicitly invoked when it applies. They make a point of reminding the reader that the Rule of Six doesn't apply to a Long Shot test, because a Long Shot test, when described in full, talks about rolling your edge dice (where the Rule of Six normally applies). The Rule of Six is not invoked for re-rolling misses.

[voydangel]

I think what Gun Nut meant was that by spending edge before a roll the only real benefit (besides the few extra dice) is that your sixes explode, whereas if you use edge to reroll you can score extra hits as normal (by rolling 5's or 6's) rather than only gaining a chance at extra hits via the exploding 6's.    Which is why it's generally accepted that edge is better spent before the roll for small pools, and after a bad roll for large pools.

[The_Gun_Nut]

Yes, that's what I meant.  I'm not sure how it could be read otherwise, since I didn't say they both happen at the same time with each example.

[Chaemera]

Sixes explode with Edge spent on extra dice.  Spent beforehand they ALL explode.  Spent after only the Edge dice explode.  If you have a large dice pool then you get more bang for your Edge buck by purchasing the reroll; you get another chance for 5's and 6's to hit instead of just 6's.

Yeah, I think it was just the wording of the underlined bit that threw me, my bad.

[The_Gun_Nut]

No problem.  I could have done it better, but I was going with the flooooow of the words.