What's the most recent build/set up that you've discovered?

And to add to it, if you haven't tried it already, the Tempest (or Geth Pulse Rifle if you want to be more lore-y) is a great gun for the Geth Engineer. Personally, I'd run either no passive (using Hunter mode as an "alternative passive") or passive/turret, which would give hunter mode's accuracy bonus, making the Tempest an absolute beast. Especially with Incendiary or Disruptor ammo, for the extra explosions. And then when you get it, Hurricane plays exactly the same way, just with about 4x the damage, and 5x the ammo problems

Or, you can use Overload+Mantis, which is also a hell of a lot of fun. Overload to strip shields and stun/stagger, Mantis headshot to finish them off.

As for the Geth Infiltrator, Geth Plasma Shotgun is a lore-friendly alternative (also good for scaring team members, because hunters are scary, rage-inducing monsters), whilst Piranha is an absolute beast on him (again, the hunter mode accuracy thing). Claymore is fun, but punishing, if you miss, you die, but also massive one-hit-kill potential. Talon is a widely considered OP option on him too, although I personally found it underwhelming. GI makes an amazing Shotgun infiltrator, just need to practice the Proxy Mine stun, shotgun cleanup method. Or, Javelin GI is crazy too, doesn't even need fitness, hides in corners, with piercing mods, kill enemies through pretty much every wall in the game.

Oh, and if your problem with hunter mode is the white overlay and not the red highlighting, there are texture mods out there for PC, that whilst a little annoying to get working, completely remove the white crap from your screen, allowing you to benefit from the skill, without the eyebleed.

Not trying to force you to use hunter mode or anything (wow, I sounded like a fanboy here), just trying to offer alternatives, even without hunter mode, the Geth Enginner is great, Tempest is still amazing on him (Also on the TSol, if you haven't tried it). Don't underestimate the Tempest because it's "only an uncommon", it's a tiny beast.

For whatever reason I never found the Talon to be that op on the GI, really good yes, but not op. For me there are two op builds for the GI: Raider and Harrier. If you want to make gold easy mode use the Harrier GI, you'd probably double the score of a Harrier TGI. Proxy debuff, Cloak, more accurate Harrier and you can wipe a spawn from across a map. With AMIII for speed or CMIV for tank it's my go to if I want to trivialize gold. I also really love the Crusader on it as well.

I finally remembered to use the Claymore Fury last night and she just destroyed Collectors with Warp IV and SAII. I never really used Dark Channel, but it was nice to use on a target at range to have a boom boom ready to go and with Warp IV the High Lord was even more brutal. Standard 66653 build with AMIII and I think I only went down 3 or 4 times the whole match.

What about the GI/Piranha? I've always heard that was the classic OP setup...

I always thought GI was most deadly with the Javelin. I would like have Proxy Mine on him, but couldn't find a way to work it into the build. I have everything maxed and Proxy at zero.

I tried the Demolisher with Valkryie and Venom. Good god is this character ridiculous. Nothing gives her trouble. And as much as I hate the Geth, its almost sad how badly Demolisher crushes them. Also tried the Destroyer with M8 Avenger for fun. Its surprisingly not bad actually. But its not really fun though.

Same exact build for me, though I usually go for Phasic ammo along with the additional piercing mod. And also to back up what @bestvolussupportau said, there's no way I would ever try to run a Javelin GI without Proxy Mine. I'm not intending to be rude either, but it's just a fact that you absolutely need it for the times when those 2 or 3 Husks are bearing down on you, as well as for assistance dealing with Phantoms as he described. The value of its debuff on Bosses alone outweighs any benefit from extra Health points, and I can't even begin to imagine the pain of a Collectors match with a Jav but no PM.

Funnily enough, Heldarion's Talon videos were the initial inspiration for me to begin my alt account odyssey, as I knew I already had a GI who could not and would not be parted from his Javelin and this setup. Other builds will work with other weapons, but I would go so far as to say that if you know you want to try the Javelin on the GI, this is the build.

I still haven't worked out how to do multiquotes, but want to add:

DistigousForest - regarding your Cryo Falcon HE, it could be inferred from your observation that some people might actually give consideration to going into battle as a Human Engineer without a Combat Drone. Those people are fools and should be eaten.

It's a great HE setup (as with the GE) but I can't read a sentence which mentions a Cryo Falcon and Geth without acknowledging the wonder of the Volus Merc in such circumstances. Probably fun enough to (almost) justify presetting the toasters as the enemy faction. Almost.

What's funnier than a Volus Merc against Geth? Two Volus Mercs. Or 4 or even 8. Along with 4 Drones and the stagger provided by the Falcon, not to mention Cloaking, it's a great fun option for payback for all the years of Geth stunlocking BS. Let's get paid!!!

Heh, my standard HE build has no Combat Drone. Too much spam of Overload and Incinerate to be bothered by the drone, plus all 6 points in fitness allows me to take a Power Amp to plat, where Drone isn't much help, instead of a Cyclonic.

Its not rude. As I said, I am still sort of new to this mode and I haven't experimented with builds as much as I should have. I would have never thought to try Fury/Claymore. Trying it led to my favorite build in the game (Fury/Crusader). So that's why I like coming here.

And I was also coming off the Turian Soldier where Proxy Mine is really unnecessary I feel. So, I thought it was similar for the GI. But I will rebuild this guy because the Phantoms were an issue and I could only deal with them with the Javelin if they weren't focused on me. Though, I did have issues hitting Abominations and Husks when they were closing in. So, thanks, I will try this tonight.