(See my reviews of the first two of these books here and here.)
I'm not as dubious about the crapsack-world trope as my husband is, but it does knock a few points off a book's total score if it feels gratuitous. Or it would if I did anything so organized as keeping an actual score for books, but that would be way more anal than I have time or inclination to manage, so we'll just leave the points-thing as a figure of speech. Ahem. Sorry. In any case, the crapsackyness of this world doesn't feel gratuitous. The environmental disarray provides a goal and a motivation - something to overcome and/or fix; the political yuck provides a source of antagonism.
So, not gratuitous . . . just a trifle simplistic, I think. But that's OK, because until I settled down to analyze it in those terms, it didn't register as such, which means all the literary devices performed as they were supposed to in making me care about and become invested in the story. Which I was, in case y'all want it spelled out. Most of the things I particularly like about the second book, detailed in the entry linked above, are still true here. Not to mention, a few lingering reservations I had about a handful of plot or setting elements were resolved to my satisfaction, making me retroactively like the first two books more, too.
In short: A well-crafted series, and one I heartily recommend. It's a little difficult to believe this was Bear's first published work - the rough edges are few and unobtrusive.