[Baal]

Here's how I see the usefulness of Afterburners. It takes 2 engines to get one combat movement point, a 2:1 ratio. Afterburners make combat movement points so at the second level of afterburners they become quite useful. Afterburner 2 makes 2 combat movement points for 20 kt, that would require 4 engines to get the same amount of movement. So, I make my fighters so they have an odd amount of strategic movement points and an afterburner 2 or 3.

I can get 8 combat movement points using 7 Quantum engines and an afterburner 3 on a large fighter. Quite impressive, considering it still is tough to kill and can deal damage.