Which characters have you extracted platinum with so far

Can I count all the barricade classes as one character? If so, all of them save 4 or so (just haven't tried them yet).

Pretty much all of them, except the Angara Avenger. Still sitting on Level 1, Rank 1.

I'm waiting for someone to mention human sentinel and kineticist and saying how easy it is for those classes, so I have the courage to try for myself.

the human sentinel is really easy. i left barricade at lv1. just use a syphon weapon

use disruptor ammo if you still have trouble.

I know, right?

That has been how it was for me, also: pretty much every character I have taken into Platinum has been able to successfully extract. This does not mean every time, because some groups just do not work.

So, anyways, in my case, the list looks like this:

1. Avenger.

Actually, I sort of lied there - I had forgotten that early on I had taken in (and completed) some platinum missions with a human infiltrator. That +40% veteran thingy can be quite helpful. But do not tell anyone, ok?

Played 1 platinum game (apex one with -25% shields/health) with the Turian soldier (valkyrie/hurricane/AR amp IV/incendiary IV), to see what the fuss was all about. We extracted (23 or 24 minutes), but man, was that painful. Everything is just a HP sponge it's not even funny. 150k was good but not enough to drag me back there.

Human Sentinel is one of the BEST for platinum (especially vs. Outlaws). I leave throw at Rank I and max everything else, electric barricade is a must. Find a corner and hunker down behind your barricade. 2 Human sentinels can lock down a room that only has 2 entrances (works best on Sandstorm vs Outlaws). Killa has some videos up of the PS4 A-Team doing this. Easy Plat farming.

So far I have used and extracted with:

Angara Avenger
Asari Huntress
Human Infiltrator
Salarian Infiltrator
Turian Agent
Salarian Operator
Angara Insurgent
Human Sentinel
Angara Exemplar
Salarian Architect
Batarian Scrapper
Turian Havoc Trooper

Krogan Mercenary because Flak Cannon is great and I don't have the Batarian Scrapper yet.

Well, my Kineticist has extracted multiple times fairly easily the times she's gone into Platinum (after the first day, where nearly every PuG failed because players weren't communicating or we had poor set of objectives: Hack, I'm looking at you).

The key thing is to know:
1. Know your kit (Kineticist).
2. Where the enemies roughly are.
3. The map.
3.a. If as you're moving to the extraction zone you see mobs ahead of you, take a (minor) detour. Seriously, 130DR with shield boost and gear only means five hits before barrier collapse, FIVE. Which normally means any mobs will have you if you happen to run into them and they're firing on you in Platinum, so taking a detour means you'll be able to survive longer and jump back into the Extraction Zone with less time wasted, and the chance to not use a first aid or revive.
3.b. As you're moving to the extraction zone, hug as many obstacles as possible along the way. This again requires 2 (knowledge of roughly where enemies are). But also in practice with 3.a. As you never know when something might just pop up in front of you.
4. Save all First Aid kits for the last few moments. Ascension DR with Shields and recharge times for Saving Barrier means you could tank the last 15 seconds if you take cover behind obstacles whilst keeping Ascension up or waiting for Saving Barrier to come off cooldown for another run.
5. Optional: If you've got Siphon or Bulwark weapons (not many have the good ones yet), the Extraction Wave would be where you switch into them (if you can as you're moving towards the zone; so last 30-45 seconds). Extra DR is always good (especially since you're largely moving as a single unit now). Siphon is not as useful, because if you're firing, you're exposing yourself as you are moving. Siphon only useful whilst in cover (at the zone only in short) otherwise, Bulwark is better.

Fairly simple IMO if your Kineticist is built for survival and you don't deviate from the above details on Extraction Wave.