Stack might until you reach the desired crit then go for power. Its how I geared my watchman sentinel.
Example, the underworld X implats that have 110 power, why would I put strength?
My implants have 142 power each.
Now I have to do the math, damn it. Each point of Strength gives .2 Bonus Damage. Each point of Power gives (approximately) .223 Bonus Damage per point. 14 Augments is 448 primary stat points, except
Vigilance gives 6% bonus Strength, and you have to consider the 5% from Sage buff, making 14 Might Augments provide 497 Strength.
497* * .2 = 99.45 Bonus Damage
448 * .223 = 103.03 Bonus Damage
So, we're at a spread of about 4 Bonus Damage in favor of the Power Augments, before we account for the +Crit from the Might Augments.
497 Strength gives roughly 1.3% Crit Chance. And lest we be concerned about diminishing returns, I used my Jugg's strength value of 3125 to figure out the value, So, if you feel that 4 bonus damage is more valuable than 1.3% crit chance (hint: it's not), then go with Overkill Augments.