Red Mars is a book that has great strengths and weaknesses. Its srengths are the process of the colonization of Mars itself. The Mars of the book is the real Mars and not a fantasy Mars and the book is steeped in its geology and geography. The time frame of the book is epic spanning several decades and multiple characters. There is some interesting exploring of ideas. In particular, it is a book concerned with political ideas and its interesting on that.
Its weaknesses, unfortunately almost overwhelm these strengths. It is very much the first part of a trilogy, so that the book ends in the middle of the action and not some natural break. Red Mars has a soap opera element to it, but this is poorly realised, especially in the first half of the book. It is only once it starts playing out against a revolution that it becomes a little better. If you compare it to something like Game of Thrones, where the world is also compelling. It has nothing like the interesting characters or compelling soap opera. Apparently, Robinson has a whole bunch of literature degrees, including a Ph.D on Philip K. Dick. However, the prose is work-a-day and the dialogue sort of on the bland side. The characters are all a little empty and flat.
However, the hard science fiction colonization is really very good. Who doesn't dream of going to Mars? If you answered me, don't read the book, because that is its main attraction. Otherwise, the book is still worth reading, despite its flaws because it is Mars that is the character that comes alive in the book.