Claire North is an author I'll read automatically. Her books tend to be wonderfully experimental affairs, that give us something we've not seen before. I still rank The First Fifteen Lives Of Harry August" as one of my favourite books. Touch and Hope were also pretty good. This book therefore has to be stacked up against those, and it doesn't quite make it.
It's an excellent book. It has a really interesting idea at the core of it, with our protagonist, Charlie, being the harbinger of Death. He is "he who comes before, sometimes as a warning, sometimes as a courtesy". This can mean he is there to prevent a death, by giving a warning, or honouring a life, by coming just before the death, or to mark the death of something more abstract, like a dream or idea. This does have the risk of the book turning into a set of vignettes, but they're wound together well, into the story of Charlie's life. They're also wonderfully ranged, through a lot of different geographical and cultural differences, that never feel stereotypical. (Though I suspect the author was fairly heavily influenced the current state of the political world, which might age the book badly.)
Charlie's life is compelling, with the experiences he goes through feeling important, as the world turns and all things die. It's compelling enough that at the end of the book I hoped for more. Which is the one "flaw" I see in the book. The book comes to an end, and all I thought was "is that it?" There was no great climax, no tying together of threads. I don't know if it's meant to tie with the main theme of "sometimes, things just end, and that's okay", but it felt incomplete. I felt that the story deserved a better ending, though, typically, I'm not sure what that would look like. It might be that the story doesn't have an antagonist. No one for Charlie to set himself against (except, possibly, the "fuckin' beltway!")
Read it. Enjoy it. Don't be surprised when it ends. And try not to expect too much of a plot. I think I might have missed it.