Perhaps the last truly excellent book by Neal Asher.
The big negative or criticism I have of his books after this one is that its very samey, in that the plot of his stories are the plan of one AI or entity (spoilers, kind of). This worked once for a series of books he did in the past, and even then everything you read that happened wasn't preordained or planned out by one thing. But since 2010 EVERYTHING is, and that for me spoils the books.
Orbus, however, isn't like that. There are characters that are powerful and intelligent, but they individually have parts of the puzzle, not all of it, so when pieces get put together there are surprises and tension and real stakes in that things could end up in destruction and death for all concerned. The characters are great, Orbus is the main character, and he has a real arc, he grows and changes, which is excellent. Sniper the war drone is back, as quippy and sarcastic as ever. Vrell has a massive part to play and has a great overall arc too. New characters such as the Golgolgoth, and the king of the prador are scary and menacing and though alien there goals and objectives are clear.
The one thing that makes this book for me is the battle, or all out war, that occurs at the end. It is by and far the best space battle I have ever read. It is superbly written and described, Asher doesn't waste page space with boring details, it is visceral, hard hitting, tense. It is that good.
This battle alone tips the book into five star territory. There are one or two lulls in the story before this point, Asher had a habit of going into intricate details about how to solve a problem, or how this character MacGyver's a situation, which is tedious. A couple of characters are just there with no real personality. However, this all leads to this epic battle, which is definitely worth the wait.
A brilliant book.