Let's see...well, the Synchronic Proton Distortion Prototype Rifle you get for completing the second Devidian mission usually chews through drones pretty fast. In space, I think antiproton weapons have a damage multiplier when attacking Borg ships, but I don't recall offhand.
In ground combat, anything with +knockback or +repel is nice against the borg (even though they are highly resistant to both). The borg's greatest threat on the ground is melee since they are designed to get up close and personal and overwhelm you. Sci officer crowd control abilities also come in handy here (+hold and +root).
Originally Posted by malashenko89
In space, I think antiproton weapons have a damage multiplier when attacking Borg ships, but I don't recall offhand.
AP has a higher crit severity, so when you do land a critical hit it will do greater damage (may still be bugged as the testing I've done in game doesn't show higher crits on average). You can also obtain very rare weapons of all types that have a 7.5% chance to proc 1000 damage vs. Borg in the Gamma Orionis fleet staging area.
From what I've heard, Phasers are worthless against Borg in space. The 2.5% chance to disable a random subsystem doesn't work against them (Since Borg have build-in redundancies). The damage is still the same as the others. You're just wasting the 2.5% chance bonus.
If you want to go cheap, get Disruptors for space combat. If you want to go 'max damage' then switch to Anti-Proton.
As for ground combat, there is never a time when you DON"T want to use the Synchronic Proton Distortion Protytpe Rifle. That thing is crazy broken against all enemies. (Although, I hear it will be nerfed come Season 3).
Other than that, I'd advise Anti-Proton or Plasma again. Plasma's burn effect is nice as it gets around the Borgs shields. Plus you can run from them while they burn. Anti-Protons built in +Crit is pretty nasty also.