On TV, this novel compares most closely to Battlestar Galactica (2003). I have no doubt that this novel was one of the touchstones behind the series being so influential in the genre of military SF.
Because this novel is a war movie, the story takes forever to wind up, as all the players need to be in their place for when the guns open fire. The first third of the book is entirely dramatic setup. You see the train wrecks going, with one model train after another ramming in the middle of a fake town, and just when you see how things are going, the narrator douses the room in gasoline and burns the house down. That's this book.
Like the best war stories, this one is filled with the brutality of war.
Myself, I found this novel almost impenetrable. With so much plot setup and so many train wrecks, I felt very divorced from the story. I wound up skimming for chapters at a time, no scene catching me at all. When action did come, I found that it came quickly, often with jumps forward in time. This amplified the feeling of disconnection for me. Skipping over the more boring narrative parts often felt like something was skipped. It felt like the editors had sliced out tedious chapters that added nothing while replacing them with nothing.
If this was a film, I would have hit fast forward and skimmed through scene, getting everything that I really needed to know at 5x the speed.
Because we follow so many characters, we don't get to know them very well. These characters are more about their situation, and how they handle the events as they unfold. Don't expect deep back stories or self-examination. This narrative is very much a forward story, dealing with the crisis at hand while while keeping an eye on the crisis dead ahead.
Like any good war story, the narrative ends at the end of the crisis. This is not a tale of the entire war, it was merely the tale of this particular moment. The war continues, both into the future and into the past.
The only idea that utterly rejected in the novel was the idea that Earth would not control a military. I didn't buy that for one second. No sane civilization let's an army run around in their back yard. Perhaps that argues for Earth being insane? I still don't buy it. Left to themselves, militaries take over and organize, so I didn't buy the fact that they hadn't already done this, as if the events of this novel were some new idea. If armies have a primary purpose, it's logistics, not fighting.
If you're into military SF, there's a big chance that you'll love this novel. If that's not your thing, you'll likely find this book difficult going.