Surviving Mars: Below and Beyond Review (rene.longoria)
This expansion is an interesting one. It does have some "grinding" element into it, going into asteroids to mine just to develop the underground is a bit of a hassle, regardless it is fun and keeps you doing something else. The underground has several anomalies, it also has two wonders to develop, which they grant some nice bonuses to the colony. The underground is a bit of a pain to explore but an RC transport full of polymers and one RC commander you can light up your way real quick.
Regarding asteroids, these sometimes have anomalies that may open mini-quest to follow up, making these interesting instead of being just "mining expeditions". However if there are no anomalies then there isn't much to do with them other than mining.
Overall it is a good addition to the game. If you have poured time into this game I do recommend this expansion. The majority of the bugs have been fixed and is enjoyable.