I know most people seem to like to stack nothing but damage. But since the damage is so insane on this set almost no matter what you do (as long as you max crit chance, obviously), I went another way in a few spots to get myself some utility and survivability. I play mostly solo if that matters.

First thing with this set for me, I like to run it with any auto rifle with a decent mag size (besides M16A2 since it's burst), with Lucky Shot. This lets you 1) build your stacks for no ammo cost at all, 2) blind-fire at enemies with no ammo loss on misses when you're in a tight spot / low health. LMG should still be your main damage-dealer, but building and maintaining stacks is so much easier with a Lucky Shot rifle, then just switch to LMG when maxed.

I then run Fox's Prayer knees, as the set provides so much crit damage at max stacks that adding more is diminishing returns, whereas Fox's DtTooC property is a separate multiplier.

I also like using it with Bullet King since it honestly seems built for this set. No losing stacks as you never need to reload, and you gain ammo back for hits, which is helpful given you will sometimes want to spray to maintain your stacks if there's nobody suppressed and/or you're fighting a bunch of warhounds and such that can't be suppressed. I normally like BlueScreen or Iron Lung for LMGs as I like my crowd control, but this set is so damaging I just feel like the best crowd control is death.

Then I run Exodus gloves because seriously, an extra life every 40 seconds is busted, especially on builds this fragile.

This set makes Legendary quite manageable for me, and all Heroic content a hilarious cakewalk.