Every 10 defense is roughly 2.356% Resistance to all damage no matter how high or low you have the stat at.
That said, your 101 Defense is around 24% Resistance to all Damage.
A rank 7 impact prism would give you 20 Defense which translates into an increase of 4.712% Resistance to all damage and having 121 Defense would give you around 28% resistance to all damage. Ideally, 100% resistance to all damage is what one shoots for because it reduces all damage by 50%.
Both, Dodge and Avoidance both have diminishing returns.
Without knowning anything else about your build and character I'll take a guess and say that the most you would get out of both would be 55% for Dodge chance and 75% for Avoidance.
Oh, and if you didn't know, Dodge is the diceroll where the percentage listed is your odds of getting a dodge and Avoidance is how much of the damage is mitigated.
If I was you I'd go for Gambler's since(4.712% translates into 4.5% all damage reduction) 4.5% All Damage Reduction is neglect-able when compared to the diceroll with a favorable outcome of 59% Damage reduction that Dodge+Avoidance would provide for you.
It also wouldn't hurt to see what comes of the dodge/avoidance (among other things) changes on PTS before going too deep into one thing or another.
If I knew more about this specific situation such as the exact stat distribution, spec tree distribution, power choice, and gear choice along with the level of mods in each and secondaries then I could comment on the exact extent of how well increasing defense by 20 is over increasing dodge chance by 133.
Sadly, I only know that this specific situation has:
Defense 101 (Around 24% Resistance to all damage. On PTS Defense is not being changed so no true point in increasing this stat by 20.)
Dodge chance 46%(On PTS if this is purely from the dodge 'stat' then this is roughly divided in half but I do not know if it is or isn't so no comment.)
Avoidance 59%(On PTS if this is purely from the avoidance 'stat' then this is roughly decreased by ~3% but I do not know if it is or isn't so no comment.)
So due to the little information and to the common knowledge of the two formulas behind damage mitigation, increasing dodge chance would benefit the "defenses" for this specific situation more than increasing defense by a petty amount.
Comments
That said, your 101 Defense is around 24% Resistance to all Damage.
A rank 7 impact prism would give you 20 Defense which translates into an increase of 4.712% Resistance to all damage and having 121 Defense would give you around 28% resistance to all damage. Ideally, 100% resistance to all damage is what one shoots for because it reduces all damage by 50%.
Both, Dodge and Avoidance both have diminishing returns.
Without knowning anything else about your build and character I'll take a guess and say that the most you would get out of both would be 55% for Dodge chance and 75% for Avoidance.
Oh, and if you didn't know, Dodge is the diceroll where the percentage listed is your odds of getting a dodge and Avoidance is how much of the damage is mitigated.
If I was you I'd go for Gambler's since(4.712% translates into 4.5% all damage reduction) 4.5% All Damage Reduction is neglect-able when compared to the diceroll with a favorable outcome of 59% Damage reduction that Dodge+Avoidance would provide for you.
Thanks
If I knew more about this specific situation such as the exact stat distribution, spec tree distribution, power choice, and gear choice along with the level of mods in each and secondaries then I could comment on the exact extent of how well increasing defense by 20 is over increasing dodge chance by 133.
Sadly, I only know that this specific situation has:
Defense 101 (Around 24% Resistance to all damage. On PTS Defense is not being changed so no true point in increasing this stat by 20.)
Dodge chance 46%(On PTS if this is purely from the dodge 'stat' then this is roughly divided in half but I do not know if it is or isn't so no comment.)
Avoidance 59%(On PTS if this is purely from the avoidance 'stat' then this is roughly decreased by ~3% but I do not know if it is or isn't so no comment.)
So due to the little information and to the common knowledge of the two formulas behind damage mitigation, increasing dodge chance would benefit the "defenses" for this specific situation more than increasing defense by a petty amount.