The SR4 rule which allow Reach to be applied as a bonus to your own pool, or a penalty to the opponent's pool is quite interesting. But how do I take advantage of this? When should I roll the dice myself, and when should I impair my opponent?

My troll has effective 3 Reach (assuming the opponent has none), and a dice pool of 16 without Reach. So, how should I use that Reach?

Try getting your gm to apply it as penalty to your oponents. lower pool= higher critical failure chance... your pool is high enough already *g*

3 Reach?
1 from Troll-Arms, and 2 from some kind of close combat weapon i presume?
You could either use all of it to give your opponent a -3 to their DicePool.
Or you could use all of it to give yourself a +3 to your dicepool.
Or you can use the 1 reach of your arms to give yourself a +1 to your dicepool and the 2 reach of your weapon to impair your opponent.
Or you can use the 2 reach of your weapon to give yourself a +2 to your dicepool and the 1 reach of your weapon to impair your opponent.
These are, technically, all allowed.
And now comes the best: you can decide what to do each time you use your reach . .

If you have more than one opponent, giving them the penalty is also obviously better than getting the bonus yourself against only one of them.

The penalty applies to the defender's defense test not their attack dice pools so the multiple opponent idea you have isn't valid.

SR4a p158, read the example.

Mesh

Yeah, I just read that, and the actual rule above it. In all cases, the character with more Reach either gets a bonus or imposes a penalty. You can choose on a per-opponent, per-test basis.

So, which is best? If you have few dice, take the bonus to reduce glitches. Otherwise, impose the penalty to increase enemy glitches. Works both when attacking and defending. (And of course, when using edge to explode sixes, take the bonus!)

Hmm. Now I'm getting ideas about a troll with a staff who just lands in the middle of a gang and Full-Defenses long enough that eventually his enemies CritGlitch themselves to death. Probably wouldn't work, but it would be funny.