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

The auto fire augment is a dps loss until you stack 20% weapon damage, and a dps gain as you stack more after that (without taking clip size into account).

Override means you can't combine the beam emitter with things like seeking plasma and it'll overwrite natural ammo types like the electrical conduits on the reegar carbine. You still get the stat changes from the auto fire augment if you combine them.

That's amazing. I've just hit level 40 in my current playthrough so I'm just on the point of building a level VI Valkyrie. If i'm right, this would mean a a barrel V + 5% passive damage in ARs means it's basically just a net clip upgrade, and anything after that would be just extra damage? Awesome.

Tried burst fire raptor and auto sweeper X. 1st one is very accurate, low refire rate between bursts but dmg sucks.
Automatic sweeper is very good. Even with penalty is ultra accurate for me and deals a lot of damage. A sort of X5 ghost but better. Added 35%+ fire rate while airborne, double mod expansion, and kinetic coil.

Was meaning to mention this but got caught up in that Kotaku author going full stalker, but anyway....

This is good shit. I tried building an N7 Valk along these lines - Beam Emitter, Full Auto Aug, Mod Slot Aug, Coolant Unit and Kinetic Coil (running Scope/Barrel/Stock) and... it's a thing of beauty. Imagine a full auto battle rifle with about 1/4 of the recoil of a stock Avenger and literally laser-accurate. 

With Clip Passive and Coolant unit it works out at a 33-round clip (providing 5 seconds of continuous beam), but it packs so much punch that overkill is a more an issue than anything. I'm expecting when I take Critical Hits, headshots are going to be almost 1 shot 1 kills. 

It works very well if you use a bio converter, and if you're using tech powers anyway then you can heal yourself with life support.

I just got back in and used my Automatic Crusader shotgun. The rate of fire isnt anywhere close to "full auto" but it has 8 rounds now and fires much more quickly than standard, and the accuracy didnt even take much of a hit! My favorite shotgun just got better.

Ive liked the idea myself, shotguns firing slugs give the feel of something like a marksman rifle, just with a large round and a very short barrel. If you take a second more to aim, the high damage of the slug is a great payoff when it hits. Though in multiplayer its better to go with something like the other N7 shotgun that has the crazy RoF, because of how fast paced and stressing the enemies can get you just need to spray and pray.

Still, the Crusader has a place in my heart. It reminds me of the shotguns id mod with slug ammo with in Planetside 2. I used to get hate messages saying i was using an aimbot cause no way a shotgun could get them at range, when in practice the slugs turn the thing into a makeshit mid range sniper rifle.

Because the Crusader is fun?

My Revenant is a bit low on damage, I didn't think about putting the full auto on the Valkyrie (since the Valkyrie is meh in MP) but according to some posts, it seems to be good damage wise so I'm gonna try it.
How is it in terms of recoil ? The 2-shot default burst already has some kick, I don't want to end up firing at the sky in full auto

I can personally attest to this. My fave weapon, easily.

It's worth remembering that even with the Beam Emitter +200% Stability boost, the recoil is still noticeable if not unmanageable. I recommend a stock on top. That + the Critical Hits passive means full auto headshots are realistic (though you still need to pull down your aim).

Don't forget about the aa12's grenade shots, accurate to 200 yards