This is, in a sense, one of the most pointless posts I've done. If you've read Time Salvager, then I can't imagine you needing to be convinced to read Time Siege, maybe you need convincing to move it up on your TBR, or just a reminder that this is out there. If you haven't read Time Salvager, you shouldn't read Time Siege yet because it won't make all that much sense. But I'll try to say a little about the book.
This book really could just be the next chapters of Salvager. It's just taking the story to the next step -- yes, there are distinct plot and character arcs, but on the whole, it's just what should come next. Making it hard for me to know what to say. Some things that I thought were pretty well resolved in Siege are dealt with again, and hopefully resolved (or closer to it) now. Some characters come back in ways that I couldn't have expected, some in ways that were exactly what I expected.
One thing that's crystal clear now -- and has been evident all along, really -- is that Wesley Chu can write a fight scene. Whether it's single combat or larger forces, he delivers. The scenes are suspenseful, intense, and believable. He captures what I imagine both the chaos and order of a battle would be like for those involved and those behind the lines.
Somewhere along the line, I got the impression that this was a duology, not a trilogy. So I spent most of the book thinking that this could be a dark, yet satisfying ending. Definitely not an "Everybody Lives happily every after" ending, but one that wraps things up well. Then the satisfying part became untenable (possible, but not likely) . . . and thankfully, it quickly became clear that it was going to be a trilogy. That said, everything is hanging in the balance here at the end of Time Siege, and it's going to take a lot of heroics for there to be even a chance for an ending that doesn't involve the doom of humanity. Even with a lot of heroics, that's a distinct possibility -- part of me wants that to happen, just to see how Chu pulls it off.
I remember liking Salvager more than I did, but whatever -- the sequel did everything it needed to do to push the story forward into the third book, with heightened action, more investment in the characters and what happens to them. Chu accomplished everything he needed to here and more. I could really use a time machine now to get my hands on the concluding volume.