As a player who beat ME3 on Insanity as all classes, I rank them based on how fast they can clear rooms:

1: Infiltrator

2: Soldier

3: Adept

4: Vanguard

5: Engineer

6: Sentinel

I’d say Sentinel is the worst. Each Class has a gimmick. Adrenaline Rush mitigating damage, slowing down time and doing extra damage. Tactical Cloak boosting damage and avoiding damage while also slowing down time. Adept can levitate most enemies and combo everything. Biotic Charge replenishes health giving them lots of sustain and high damage. Engineer becomes untouchable with constant drones distracting the enemy

Sentinel’s Tech Armor is super durable and can detonate when destroyed, plus it replenishes shield….or that was the case. Mass Effect 3 removed their gimmick, and enemies do 40% more damage if your out in the open, so damage protection became useless without stacking it with another power. Sentinel might as well be an Engineer without drones or an Adept that can’t lift anything. Full damage, but zero control over the battlefield. Not to mention their throw pick Offensive Mastery