Best/most fun uses for the Auto, Burst, and Single fire system augments?

Automatic Mattock or Halberd, of course. heh. It's pretty fun. Not very accurate but great at applying ammo effects.

Does it actually give a laser beam like remnant weapons now?

Nice, wonder how that'd work out on a reegar or ghost

Can you craft a Halberd now?

I created an electro firing burst black widow.

It was shit.

Ah, good point. I was thinking weapon mod, not crafting mod. I forgot that it was applied to the Mattock during crafting. Well, I've yet to get to Kadara yet so we'll see if the Halberd shows up as being able to be crafted.

It doesn't, not from what I could see anyway.

On the other hand, with the various fire augs now easily available, there isn't a particular benefit to crafting halberds. The Valkyrie in particular seems to work well with both single and auto augs for the purposes of a vanilla and auto Halberd respectively. 

Any way to make the falcon decent? I love having a dedicated grenade launcher but its kinda bad

Is it better to go with full auto or beam emitter on the valkyrie?

Apparently both the valkyrie and hornet are doing twice the dps of other weapons.

I didn't use the fire type augments much in my first run through as I was concentrating on sniping and everything I tried seemed to make it worse. In fact even on AR's and Shotguns I could never really find an augment I liked.

This second run through I tried the beam emitter on a Valkyrie and it's pretty amazing. Definitely keeping that combo!

Has anyone found a use for the grenade one? I tried it on a Side Winder but it seems pretty awful!

Ah right, I thought you meant they were doing 100% more DPS then they should be. Yeah, both of these weapons were specced with burst firing in mind. In full-auto aug's case, you're paying for that with burst-level recoil, whereas with the Beam Emitter you're not getting any clip extension without adding any extra mods/augs.

The Beam Emitter does something weird with clips, though. I'm not sure every 'shot' it fires equates to a single 'round' in the clip. For me, my laser valkyrie (I call it the N7 Scythe, after the very similar gun in Helldivers) maintains it's 500rpm fire rate with a 29 round clip, which equates to around 6 seconds of continuous beam. Unless my math or understanding of the rate of fire stat is wrong, (500/60)x6 equates to 50 'rounds' fired in that same time. So it might be fine.

My advice? Just try it.

Speaking of this, where can you buy them? I have only seen them on the general vendor on the Nexus, and even there you have to board the Tempest and come back to refresh the list, and it's randomized.