I finished Cixin Liu's The Three Body Problem, but I'm not entirely sure what to say about it. It's part of a three part trilogy, so it seems unfair to judge it without seeing what book two has in store. That said, it's a weird book.
Maybe it's a first contact story, or maybe its a history of the Cultural Revolution, or maybe it's a conspiracy story, or maybe it's a little bit of each. I can't really say without some fairly major spoilers.
The prose itself is okay, if not particularly exciting. There are some interesting big ideas here, including a proton-sized computer unfolded from seven dimensions, using the sun's gravity well to boost transmissions, an online game about the three body problem, and some early seemingly impossible acts eventually explained in a scientific manner.
The characters are largely cardboard cut outs, with the exception of one of the main characters, who we follow through a long history. Liu has so much stuff going on after the opening that there isn't much time to spend on characters.
If I didn't know it was one of three, I'd say it was the grimmest first contact book I've ever read. But there's no telling what's going to happen next volume, so I'm not sure. I enjoyed it, but found some of the choices baffling, and was left at the end without much enthusiasm.