fwiw I found Red Mars to be a pretty boring, badly-written space soap opera (and murder mystery for who-knows-what-reason) with caricatured ethnicities.
Having read the trilogy (as well as "2312"), I must agree that it was poorly written, with some very poorly constructed characters. Having said that, and despite my distaste for and disagreement about the political outcomes, the technical vision was very interesting.
In terms of expansive universes, I would recommend the "Revelation Space" series, though it is much higher-level than the Mars trilogy. I am also a big fan of the action-oriented "Expanse" series (by James S.A. Corey), as well as the crowd favorites: "The Martian" and the "Foundation" series.