These stories are leftovers, the musical equivalent of bonus tracks, from Kim Stanley Robinson's Mars trilogy. For sure, they should not be expected to be on a par with the proper trilogy. Despite the mixed reviews, I wanted to read this, a couple years after having finished Blue Mars, because I loved the world and characters Robinson had created, and I was interested in one last visit to this wonderful place. Some of the stories succeed, particularly those that follow Roger, the "Green Mars" story being this book's centerpiece. The stories involving the Martian Constitution are surprisingly interesting. But some are terrible, especially the one-page "story" that merely lists what music Robinson listened to while writing for particular characters. By the time I got to the poetry, I was more than ready for this book to be over.
The book is good enough at its peaks, and evocative enough about Robinson Martian vision, that I feel it's a worthwhile read overall for those who really loved the Mars trilogy. But it should be taken for what it is: Extra. Not a proper short story collection or coda, not a masterpiece.