viral +100% damage vs grineer and lowers max health. corrosive +75 vs grineer but reduces armor.

What status is best for Grineer?

If you're facing off against the Grineer, bring Puncture, Radiation, and Toxin. If you're going against the Infested, then Slash, Corrosive, and Heat are your buddies. If the Corrupted are your enemies, Corrosive and Cold will be most effective.

What is viral damage good for?

Viral damage is Virus. It amplifies damage to the health of the afflicted target by 100% for 6 seconds. Subsequent procs add 25% increased damage to health up to 325% in total after 10 stacks, with each proc having their own duration. This effect will work even when the health is protected by armor ("yellow health").