I posted this in another thread, but I figured a lot of people probably never seen it and would like any help they can get getting by the Collector Ship trap on insanity.
To start, I'm an NG+ Infiltrator and I picked assault rifle training as my Collector Ship weapon upgrade my first play through. My bonus power is Geth Shield Boost. The Heavy Weapon I recommend the most is the Collector Beam Weapon, as it burns through barriers like a hot knife through butter.
My main recommendations for starting this mission are to pick a squad member with warp and an SMG, and another who gives the Squad Incendiary Ammunition talent. While Warp ammunition would help, Jack wasn't a good choice for this mission because she has neither warp or the ability to instantly recharge her shields like Grunt or Jacob, who also give Incendiary Ammunition.
I look at this mission as three major encounters. 1. The Trap, 2. The Praetorian, and 3. The Scion and Husks.
1. The Trap.
The first part of this mission is arguably the hardest point in the entire game, and it caused me countless restarts until I worked a system out, in which case it's mostly important to stick with it until you eventually get past this part.
Before the first platform arrives, equip as assault rifle/SMG and have your Incendiary Ammunition squad member activate that power followed quickly by their shield (in Grunt's case, Fortification). Leave your squad to their own choices of cover, as they will move according to the situation. As the platform touches down, IMMEDIATELY have your warp squad member activate that power and proceed to shoot the three Collectors as fast as you can. You should be able to burn through most of their barriers, and possibly have their health fairly damaged before the Harbinger possesses one. Don't fret, just switch to the Collector Beam Weapon and keep your fire concentrated on the Harbinger. As soon as his Barrier is down, switch back to your rifle/SMG with Inc. ammo and keep the fire up, while ducking and moving back and forward behind the main console for cover. Get used to his patterns, the main one you need to worry about his the slow moving blackish ball that will knock you out of cover. If this connects, try to get back behind cover IMMEDIATELY. One or both of your squadmates are likely down at this point, try to revive them the best you can. If your shields are knocked down, pop your barrier. It will instantly recharge your shield and has for me been the difference between life and death. If your character knows Incinerate or any armor damaging power, use it as much as you dare. The important thing is to have the shield ready.
The second platform should arrive before the Harbinger dies, or just after. Repeat what you did for the first platform, and if you have a sniper rifle, make use of it to try to kill one or two of the Collectors before the Harbinger arrives again. When he does, keep your cover and take out the Beam Weapon again, and once again stop when the barriers are down on the Harbinger and switch back to your rapid fire incendiary weapon.
If you survived this, (you will have to revive your squad often, but wait for the next part to past), you will get a chance to fight the Scions. Bring one down to NEAR death, where a single Incineration blast or a sniper shot will take it out, and start working on the next one. The next platform will NOT arrive until one of the scions are dead, and if both are literally a hit or two away from death, you can kill them both before the next platform even arrives.
The final part of the trap is yet another platform of Collectors, keep your squad revived and repeat the previous strategy and you have a very good chance to beat that part.
Part 2: The Praetorian.
I've read a lot of people have struggled with this monster, it was actually the easy part of this mission for me with about three tries using tactics any class can use. Something to keep in mind is the Praetorian WILL NOT target your team mates, but the shock wave it produces when it charges it's barriers will kill them, so it will always follow you. Your main concerns are the group of husks and two collectors that are going to ruin your day, Have your squad focus on the Abomination/ Husk rush and the two Collectors that show up and you will be alone to fight the Praetorian.
The ramps going down from the door you entered the room and the floor hugging the ramp's walls is crucial for this fight. The ramp area is shaped like an L, and this is where you'll want to stay for the entire fight. As soon as the door opens and Husks and Abominations come out, concentrate your fire on them with sniper rifles or rapid fire Incendiary ammunition until the Praetorian comes close enough to be a threat. Always, always keep a tall piece of cover between you and it, as being caught in the open is almost always a sure death. It will not target your squad, for some reason, so space them out and have them use their powers on the two Collector drones that appear. I did not have Harbinger appear, so I do not think you need to worry about that threat. Once the Drones are killed, it's just you and the floating jerk with laser eyes. As Kal Reegar said, "Kill it with bug bites". Just keep your automatic weapon with Inc. Ammo on it and a pillar between you and it, it will follow you around in a very predictable way, and when it starts to get close, RUN to the next piece of tall cover, hugging the wall as cover. Do whatever it takes to eat away at it's armor and barriers, it's going to be a slow going fight, but as long as you keep ahead of it and know when to move, you should not have a problem killing it. Just remember not to engage it while stuck behind cover. That will just ruin your day. Infiltrators are lucky here since they have the cloak, which comes in handy, but make sure you keep your powers free for the shield boost when you need it.
And the third part is easy, but I can see some people getting overwhelmed by the large numbers of Husks and Abominations. Once again, keep your Inc. Ammo activated. After you clear the area after the Praetorian of Collector Drones and Harbingers, the door at the far end of the room will have a Scion come out. There is an elevated area above the Scion you should engage it from. Just move every time it takes it's shot, and pop your shield boost power every time it hits you. It'll go down in time. After you are prompted by Joker to get the hell off the ship, you will end up in a hallway with a ridiculous amount of Husks. Keep your team mates out of cover and use close ranged/automatic weapons on them. Run up and down the hallway to the opposite end to spread out the Husks if you're alone at this point, and just chip away at their defenses until they drop, one at a time. If they get close or look like they're about to trap you, punch a hole through them and sprint right back where you started, and repeat until they all die. When you deal with that threat, there is absolutely nothing left to fight, so run to the shuttle and celebrate in whatever manner you deem appropriate.
This mission was stupid, stupid hard so I hope that helps people.