Velocitus competes for the title of the highest damage weapon in the game, all normal and Archwing weapons included. It also has built-in punchthrough, pinpoint accuracy (though it's not hitscan meaning you need to compensate for travel time when firing far away) and it's the only Archwing weapon that never has any ammo trouble even with Automatic Trigger. When you need pure damage, it's the way to go. It does over twice the sustained DPS of any other Archwing weapon, which shows in the Golem-fight in particular (also in the Balor Fomorian fights during the Eye of Blight) - people with fully modded Velocitus kill the Golem in seconds while most players take minutes.
Other useful Archwing weapons are the Grattler & the Fluctus. The Grattler does very decent AOE damage at shorter ranges and the explosions can hit through walls. Careful in close quarters so you don't blow yourself up. It also has the second highest DPS overall out of all the Archwing weapons, though its limited range is of course an issue.
The Fluctus comes with built-in 275m punchthrough allowing it to hit targets through any walls and the wide waves annihilate enemy masses. It's the best weapon for clearing masses of low level enemies up close, so for any Corpus Trenchrun mission really. Unlike the Grattler, it can't self-damage either. Its biggest weaknesses are the lack of proper long range option if you do pick the Fluctus (annoying especially in freespace combat) and the poor ammo pool. Its damage is sufficient for clearing masses but it's a far cry from the Velocitus or even the Grattler.
Finally, Imperator/Imperator Vandal/Phaedra are all good generalist guns. While they show projectiles they are actually hitscan; the tracers are only visual. Phaedra does significantly more damage but suffers of inaccuracy. Both unfortunately have damage falloff so they suffer at longer ranges in spite of their hitscan nature making them fairly easy to hit with. For long range use, I rather recommend you learn to compensate with the Velocitus and use that instead.