I don't profess to have the exact answer, but i suspect, repel will push you away so far where as knock back will throw you back with a chance to knock you over.
What's the difference between knock back and repel?
Repel doesn't knock you over and doesn't interrupt you. Using knockback on someone trying to aim with a sniper rifle will cancel the shot, using repel will not (unless they're pushed out of range).
I find repel useful in PvE when playing with my engineer because it can be used to push enemies right into chroniton mine fields.
Repel: When the hot chick at the bar gives you such a withering glance that your testes shrink and you skulk away in shame, wishing you had never asked her to pass the salt.
Knockback: When her WWW champion boyfriend takes you out back and beats you into a paste.
Comments
Repel doesn't knock you over and doesn't interrupt you. Using knockback on someone trying to aim with a sniper rifle will cancel the shot, using repel will not (unless they're pushed out of range).
I find repel useful in PvE when playing with my engineer because it can be used to push enemies right into chroniton mine fields.
Knockback: When her WWW champion boyfriend takes you out back and beats you into a paste.