How much stronger is the reapers toll/treachery/gface vs insight/fort/andys for a hammerdin merc or is it even at all?

They’re both better than monsters in hell but the reapers build attacks and kills faster especially vs bosses with the cb from guillaume

Would it be better to use a fort for the reapers build rather than the treachery?

I often switch out the Fort for a treachery in the insight build. The ias and fade are very good

No, treachery is better merc armor:

https://forums.d2jsp.org/topic.php?t=54233648&f=87&o=0

"4. What is all this topic telling me? ISO tl;dr version
Answer: Treachery is simply better than Fortitude. In ~80% of all cases when raw damage is applied, and better in ALL cases in which CB is applied. In the eventuality of killing a mob, Treachery kills faster. It also makes for a better shell for the mercenary to be a stronger tank."

The problem with that guide is it assumes you are using might merc. Well no shit fortitude isn't going to be as good if you already got 260 ED on both mercs. It also uses GT instead of any other polearm which, yeah the difference between 45IAS is going to be frames higher.

If you do not use might merc, I'm going to hazard a wild guess that the 300% ED is better than attacking a frame to a frame and a half faster. While that can be as fast as 24% faster attacks, the non might fort build is hitting twice as hard as the non might treachery build. Mercs only jab twice too which that guide does not account for, which is probably why pages later the treachery build was only like 10 seconds faster at killing hell baal than the fort build was.

There is that and the issue of defense. Fort mercs get like 20k defense thanks to chilling armor, treachery mercs get a whole lot less. Since act 2 mercs dont block, stacking defense isn't a dumb way to mitigate damage when they're being attacked by five minions of destruction. If it drops his chance to get hit from 70% to 40% thats a 57% decrease in amount of times he is hit and the true calculation is probably more than that. That kind of reduction in hits taken slaps 15%dr out of the water, otherwise youd see more shaftstop mercs and you just dont.

The guide then says that chilling armor needs to proc too but 15% is way more likely than 5% and the extra defense is just a bonus that is far more likely to happen, treachery mercs survivability depends on the res from fade.

Yeah treachery is better when you have seven other characters in the game stacking all the auras but for standalone play or if you use holy freeze or whatever I just dont see it.

Thanks for this detailed response. Very informative!

I guess to answer your question the guilly treacher reapers would be superior as you have conc.

Would gface w/15ias, reapers, and fort be better than using a treachery for a holy freeze merc?

no,treachery is a lot better for a hdin merc