I posted a few days ago, asking what builds everyone was running. Since then I have hit on what might be my favorite build as someone who hates to be pinned down in intense firefights. I'm using the light, fireproof armor, along with the Double Edged Sickle for basically unlimited firing (Technically I catch on fire after about 14 seconds of holding the trigger, but if it isn't dead in 14 seconds I deserve it) For my secondary I'm using the handheld anti-tank pistol. And I carry thermite grenades. I call the Quasar Cannon and the Jump Pack stratagems, plus 2 of whatever the specific mission calls for. I also need the Vitality enhancement perk to survive the low-level damage my gun does to me.
I have leveled up on the Double-Edged Sickle to where I can put the 4x scope on it, and it is basically a zero-drop sniping beast. Put the dot on the face of a Heavy Devastator and squeeze the trigger until it dies, all while being WAY out of range.
Generally I hop across the map with the jump pack, get to high ground over the objective and provide overwatch for the other members of my squad, who are more brawler types in heavy armor. With the Quasar I prioritize gunships, dropships, war-striders and hulks in that order. Everything else I take down with the Sickle. The anti-tank pistol was mostly added for the occasional suicide mission, but it is handy if the bots are clustering up below my sniping nest and I want to thin them out a bit.
The upside of this build is that the Sickle and the Quasar are unlimited ammo, so I can camp up on a good cliff essentially forever.
On missions where we will have to sit for a while, such as geologic survey or extract civilians, I also like the EMP mortar with the actual mortar to freeze groups in place and let me pick them off while the actual mortar shells pummel them.
What are your non-standard builds and play styles?