Just finished it. Two thumbs way up. At least as good as Derelict, minus Derelict's FREDding errors.
One observation, though. I accidentally broke a mission by giving a guard order to Alpha 3. Whenever you need for a fighter the player can give orders to to go do something, use the clear-goals SEXP first, then the AI goal, so that the player can't break it, since player orders take precedence over any you give in the FREDding.