I finally got to play terraforming mars yesterday. 4 new players and the owner giving a very concise and thorough rules overview. It was way less complicated than I thought it was going to be.
Everybody had a great time, even the often surly player couldn’t help but be dragged into the theme. I suspect having 5 players let us each keep an individual flavour to our tableaus. It felt a lot like race for the galaxy in that regard. Perhaps with 2 players we would end up building everything and the kitchen sink and that individuality would disappear.