I stick with Pod A, does great damage and I usually focus on one enemy at a time.
The weapon I've managed to fully upgrade so far is the Virtuous Contract.
I stick with one loadout that is pretty much attack/heal. I find their speed to be fast enough to not want the movement boosts. I have auto heal, deadly heal, healing when attacking, shock waves, attack boosts, and some HUD conveniences off the top of my head.