I use the spear for all bot missions. One thing I would point out on factory striders its a bit difficult to one shot em on the weakpoint cause they have to face you. Otherwise the spear work amazing against everything else, as long as you have decent ammo supply
Bots? Yes. Bugs? No Unless im doing a challenge, i always run sprear vs bots. Tanks? 1 shot if lock on turret. Walker? Take out top gun easy. Turrets? Deleted. Hulks? Poof. Fabs? Donezo(which can include strat jammers). I perfer eats or RR for bugs.
I don't understand the crossbow main...when you have the counter-sniper rifle that pierces med armor and has 15 rounds...it one-shots devastators in the face and takes down other medium armor. Recoiless Rifle and Auto-Cannon feel superior still. I even go with the commando rocket and shield so it doesn't take up a back pack slot and has 4 shots that are laser guided and refreshes almost as fast as the EAT.