Your primary armored DPS that isn't a Manticore. In most cases, a Manticore is scarier, but these guys have consistent output and are also armored. And unlike Manticores, you get all 5. You can think of them as armored Jaegers that do better vs high HP enemies and same-ish or worse vs. lower HP enemies.

The big thing about them is their skills. They get bonus damage based on how much max HP a target has, and they can drive their own crit rate up as they keep firing.

They do however, apparently have defective targeting systems, so you NEED something else like a Jaeger to provide range, because otherwise they're kind of not going to spot anything to shoot.

The SWAP Striker has higher offensive stats, better multipliers, and notably higher accuracy than the base version, so it can actually hit things. The main downside to this is it costs 6 instead of 4 to put into your echelon.

Almost across the board, it's an improvement for the Vespid. However, its a pain to get a full formation of them because its a 2 star base unit, and as a DPS unit you want it at full stacks. Also, it's not really significantly better than stuff like Jaegers and Strikers. They're not useless, but there are just much better SF units to spend effort and slot points on.