My favorite so far has been Operation 1, Mission 4.
Marines get some fun toys to play with, including the BFG, and the Invader has a nice selection of badassery to deploy with the recommended Invasion card.
Same as me. Operation 1, mission 4. Invader won.
I played with my friend, and he picked 2 marines, 2 main actions for each marine.
This game was so close. The objective token was 2 blocks away from its destination.
One mistake could be the game for the other.