If you don’t already have Offworld Trading Company and would like an RTS that focuses on economy, plays at the pace you want to play and has really intelligent AI players that you can configure you should definitely go grab Offworld Trading Company.
The first major DLC was just released for it, The Ceres initiative. The base game takes place on Mars. By contrast, Ceres takes you to the largest asteroid in the Mars/Jupiter asteroid belt and adds new resources and structures. From a replay point of view, it really changes things up because you’re battling diminishing resources.
Go grab it here: http://store.steampowered.com/app/511450/