Continuously chaining more than 2 attacks gives +2-5% Power. Stacks 10 times.
Up to +5-20% Strength based on the charge time of your heavy attacks. Stacks 3 times.
+10-16% Toughness on Critical Hit Kill.
+1-4 Burn Stack(s) on Critical Hit to a maximum of 3-12 Stack(s).
Depending on weapon choices, you can vary some passives up.
I like this for constant toughness regen for the whole team, this is built to be a supportive team player, and to help carry teams through really difficult encounters. Overall, you have a ton of ways to choose how you want to approach enemies.
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Either laspistol is fine, and melee weapons should have a focus on being able to kill elites with ease.
Good Luck and Tag Everything! :)