Profiles and Tactics.

Key passives - Omni vents, life support system, fusion mod of adrenaline, and shield oscillator in chest.
Weapons - hornet (auto fire systems, beam emitter, bio converter) and ushior (bio converter)
Explorer - turbocharge, energy drain (prime+damage spec), lance (shield powered).
Sentinel - singularity (exploding), energy drain (prime+damage spec), lance (shield powered).
Adept - cloak (escape artist), nova (priming), throw.

Sentinel is my primary profile and I use it to kill regular enemies. I prime with singularity, combo everything possible with lance, and try to finish off enemies by exploding singularity to instantly recharge it. If I run out of shields/health or if singularity goes on recharge, I've got energy drain to fill up my shield and health (via life support), prime/detonate to land a kill and get singularity back, and trigger omni vents if I can't get a quick kill. Everything from the profile benefits me: combo damage is obvious, tech recharge speed helps when I can't get an easy kill, power shield cost makes lance cheaper, restoration lets me get a full shield out of energy drain without having to take the shield evolutions, and tech armor is very nice on a build that depletes its own shields. I wish it had biotic jumps though.

My explorer profile is for killing big guys, I pretty much just hit turbocharge and can melt almost anything in seconds. It's an extremely effective but pretty boring power and I'm not sure what I could replace it with for killing tough enemies. Maybe cryo beam specced for armor debuff. Blink is unreliable but fun and usually makes moving through cluttered areas faster. Weapon damage and damage resistance bonuses are universally useful, tech recharge is useful to pretty much anyone using tech powers, biotic damage isn't as good as combo damage but still benefits lance, and power restoration is useful for anyone with active defenses. It's a pretty great jack of all trades setup that still leaves room for other profiles to be useful in particular roles.

The adept profiles focuses on biotic aoe so I've combined it tactical cloak to maximize nova's damage, and then use throw to finish off enemies primed by nova. I picked escape artist because otherwise tactical cloak prevents life support systems from triggering, which is a problem when using bio converters.

The vanguard is okay, but siphoning strikes just doesn't seem to cut it on insanity and the melee damage bonus isn't huge. It is the only profile that gets biotic recharge speed, but I've got omni vents and the adrenaline mod for that. I might make a fun build for it eventually like charge, backlash, and flamethrower.

The engineer was one of my favorites in previous games, but unfortunately I don't think it's very good in Andromeda. It's too focused on constructs, which aren't really strong enough to make a build around, and the tech recharge from the drone is less than what the sentinel, explorer, and infiltrator get.

The only really good thing that the soldier gets is weapon damage, which is just one of the things the explorer has. It's damage bonus when killing enemies is kicks in at the wrong time: you want it more at the beginning of the fight when you're dealing with the most enemies or against single tough enemies that take a while to kill. I kind of feel like the profile, and the combat tree in general, is designed to avoid being outlandish above all other considerations.

I think sniping gets pretty boring in this game as enemy AI can't handle long ranged combat, so I haven't played the infiltrator much. I find I can often guess where an enemy is behind cover pretty easily and I don't like the FoV loss from scopes so seeing enemies through walls doesn't appeal to me. I haven't noticed the cloak evades doing anything other than looking neat. It's a good profile with solid bonuses though, but it's just not how I want to play.

It bugs me that there are profiles with biotic damage when most biotic damage comes from combos, but no tech damage when tech abilities have a good amount of damage outside of combos. The fact that there are no bonus for combat powers in any of the profiles suggests to me that the devs weren't very interested in them either.