Surviving Mars: Below and Beyond Review (Wilderking)
I was hesitant to get this expansion due to all the bad reviews, but honestly its not as bad as everyone makes it seem.
Havent come across a single bug.
Sure, you can easily play without the asteroids and the underground, since they feel "separate" from the main on-ground gameplay, but on the other, it gives you extra things to do and manage which is quite fun. The underground also has Buried Wonders with varying effects. The Bottomless Hole for example gives like 3 or 4 extra breakthroughs, which is always nice.
Transporting resources underground aint difficult either, if you just use shuttles (underground) and set the elevator to have a reasonable minimum amount of resources, so there is a constant availability.
In short, this expansion aint mandatory (like green planet, which imo is an absolute must), but is still a nice add-on to the gameplay!