I loved it, but then again, I almost always enjoy Roberts quite a bit - he's very much a writer who wants his readers to think about things, not just enjoy the ride (which is, for this book, is an excellent ride indeed).  I've seen where people have complained that for one reason or another, Robert's New Model Army wouldn't work.  That's as may be, but I think that those poeple are missing the point - Robert's real focus isn't the classic military SF war-porn, but is instead a thoughtful exploration of violence and war.  The book is really three mini-books in one, each one very much different from each other (hard to talk about without spoilers).  Despite this, or perhaps because of it, the book really hangs together and feels like a bigger book than it really is. The ending walks a knife edge between falling flat and being brilliant, and I chose to believe the latter.  Don't hesitate to read it!!

The Atlantic article was a fascinating read.  I'm not sure how apropos the slime mold comparision is, but it's interesting to think about.