This book is clearly the first in a series. The overall structure has a theme of humans facing extermination by an overwhelmingly numerous alien enemy. Clear similarities to Ringo's Posleen series. Perhaps overly so. It could seem like Ringo is recycling too much of that series. There, however, we at least get some glimpses into the enemy's mindset, no matter how superficial. Here, there is absolutely no such analog. The enemy is depicted as robots, with no insight into even the CPU of a master controller. In terms of character definition, this is even more awkward than David Weber's In Death Ground, where at least the alien controllers/generals revealed some of their reasonings.
The book commences with a contemporary bang. Giving a detailed battlefield description of US troops in Iraq. You might compare this well with the opening scene in Starship Troopers. This chapter sounds like Ringo's touch.
To readers of an engineering bent, VNW offers a fascinating look at how spacecrafts are designed at NASA. Early chapters show the many technical issues that have to be dealt with. Like why you see a star scanner for navigation. Or an Attitude Control System. I used to be at the Jet Propulsion Lab, and this part of the narrative is very authentic. Of course, it's heavily dramatised and sped up. But still, you get the flavour of what actually goes on. I'm guessing that Taylor wrote this section of the book, given his background.
But there is an awkward implausibility. Bots desire iron. In various scenes, they are shown as quickly tearing down buildings to pull out the iron rebars, for example. Now, it's one thing to mine Mars and the moon for this. Bots need an energy source. Usually, in scientific speculations, it might be solar energy. Necessarily slow, because the amount of solar insolation you can collect limits your extraction rate.
However, when they are on Earth, what is this source? And, even assuming that collectively, the bots have sufficient energy, perhaps located at one of their factories or landing points, how is it stored in each bot, in order for it to move and to extract iron? There appears to be nothing like a conventional fuel tank.
Could it be radioactives? They use these for control logic. So could they also be using them for fuel? The plot does not rule out the latter. If so, there is a huge problem. Radioactives are very scarce, on a cosmic scale. The bots desire iron, and that is relatively scarce, compared to hydrogen or even carbon. For example, the bots disdain carbon; it is everywhere on Earth, and far more abundant than iron. Makes sense. But iron is also far more abundant than radioactives. It doesn't compute to expend the latter to get the former. Sure, maybe the bots mined sufficient radioactives on Mars, and took these to Earth to power their operations here. But you're still swapping an expensive item for a cheap one.
Well, what about antimatter? A more powerful energy source than radioactives. But this is even less abundant in nature. It could be manufactured in industrial quantities, with sufficiently advanced technology. However, this might need massive energy input.
Of course, this is science fiction. There could be some heretofore, unknown to our physics, energy source. After all, many great SF plots invoke at least one major physics extrapolation. Say a hyperdrive or time travel. Think of Asimov's Foundation series or Anderson's Time Patrol. But this brings up another problem with VNW. The authors repeatedly eschew unconventional physics. The bots communicate by radio signals, using encoded frequency hopping. While it is strong encoding, the methodology is well known to humans. In part, the authors have done this to let the humans have a rational handle with which to understand and counteract the bots. No Harry Potter magic here. Very commendable self-imposed intellectual discipline. But if the authors continue this internal consistency into the next book, they could have dug themselves into a hole. They might need a plausible and ingenious way to reasonably explain how the bots get their energy. Without pulling in some brand new physics.
You see, those books that I gave as examples intricately wind the physics extrapolation into their plot structures, from the get-go. In the Foundation series, for example, the hyperdrive does not first appear in the second book. It is needed for the very definition of the first book's plot. For the second VNW book, any rabbit from a hat might look strained, a deux ex machina.
Aha, but what about Stirling's Nantucket series? That alien ship in the first book. Is it not deux ex machina? Only to a limited extent. It appears only in the opening scene of the first book. For the rest of the series, there is a rational and consistent unfolding of the plot. No more rabbits. You can do this, carefully, at the start of a book, far more easily than later.