After using all 3 of these weapons as a gunner / bomber (no sword!) I believe:
1) AP is useful only in fsc. Out side of fsc it's damage isn't so good, but in fsc most of the mobs are weak to either piercing or elemental, and for some reason AT THIS TIER it gives orange numbers. The numbers still aren't very impressive, but you can fire 5x shots w/o reloading so the damage does add up.
2) Polaris has most awesome crowd control as well as aoe damage. Sometimes you might find difficulty getting the knock back "just right" or getting 2+ shots when it knocks back at max range, but this is out weighed by how naturally it works in other settings. Having a 3 shot clip also means you can shoot 2x times w/o reloading, which is VERY useful.
3) Storm Driver imo has now officially been out classed by these other two guns. Previous to the Polaris balancing issue and me actually taking an ap into fsc I believe the storm driver was just amazing. But now - the Polaris has better utility, and damage, and is easier to use. The AP is just too good of an fsc gun to pass up...
What are everyone Else's opinions on these guns? Agree? Disagree? tell mi pl0x
Well, Storm Driver has one thing the other two don't.
Storm Driver's charge attack can be godlike. I'm sure you've noticed it yourself, at times. It has this nice habit of ricocheting on the enemy shot, causing enough damage to instagib gun puppies in a party of 4.