Overall, it’s a pretty good book – I’d give it three stars. The action is engaging, the science is solid, and his invading aliens have unique motivations and modes of travel. (It’s important to figure out why they are moving so slowly.)
But it’s not a 4 or 5 star book.
Sword is in many ways old-fashioned. Chapter 1 is a temper tantrum thrown when a wealthy alt-space guy can’t convince NASA with five (5) (five!!!!!) months of telescopic data that the aliens are coming. After five months, with dozens of telescopes and hundreds of astronomers looking, everybody would know the aliens are coming. Yet NASA somehow keeps the lid on the invasion for decades.
So, in Chapter 3, wealthy industrialist decides to invest his billions in developing and building the type of tech we’d need to defeat the invasion. This goes surprisingly smoothly, despite government interference (of course the government interferes – ignore the fact that they’re paying SpaceX and others) and has few technical glitches. (It’s only rocket science, after all.)
Oh, and there’s a hijacking of a ship that I saw coming for a while. And the US Secretary of Defense has to be fired in order to put a stop to his obstructionism. (It’s only an alien invasion.)
Now, despite all of this I did find the story entertaining. Also, the aliens were unique, so it’s not all recycled material. But there’s a lot of recycling going on. It was enjoyable, but cotton candy for the mind. It will not be on my Hugo list.