Recently I have found the thruster demo in the content examples.
And I know that one can also apply forces to a rigid from a BP via the Add Force node.
So … in what situations do I want to use which of those two options?
Thrusters use Add Force at Location (internally) so use whatever is easier for you I would say 
I see, thanks.
Thrusters are safer way of playing with physics. Also for add force you need to compensate for tick, (i think divide force by tick delta time), because plain adding on per tick basis is very fps dependent.
If you do velocity change or add impulse, (or manually change location of physics body) it all messes physics simulation. because sudden change of speed or location means huge (sometimes insane) acceleration or something collides when it should not. This sometimes results in very fast moving objects.
I don’t think you need to compensate for tick while adding force, I agree with TK master, it is the same.
Impulses are different, it is a one shot force such as when firing a projectile, versus applying a constant force such as gravity.
Yup, forces already * by deltatime which make them ideal for pushing objects over time… and impulses are meant for instant one-shot. So you don’t really need to manually mess with delta time.
Just for the records, I found this answer from Ori Cohen (Epic Staff), I hope he knows what he says 
According to him functions like AddForce are framerate independent:
Cheers!