The Engineer class allows for the player to defend themselves from a range of synthetic and organic enemies.
The Engineer class can take out robots fast and easy once you upgrade the Overload and your Engineer class skills.
Taking out the synthetic units that support the enemy units will quickly give you an advantage in the battle.
Additionally, the Overload can be used to take out the shields of enemies fast so you cut them down with your gunfire.
For the biotic enemies, you will need to send out your drone to wear them down and equip a machine pistol that will be effective against barriers, after that it's easy to trip them apart.