Alien Echoes by Mira Grant was an interesting take on the alien universe. The first half of the book was an excellent and gritty story about the struggles of colonies, with fascinating extrapolated biological issues.
When the aliens come crashing down, it’s clear that they’re trouble of a wildly different scope — too perfect to be accidental. Olivia offers fascinating viewpoints — she explains what’s expected and what’s really unusual (from an amateur Xenobiologist’s POV), which proves to be a fascinating breakdown of plausibility for the various alien traits.
Neuromancer by William Gibson is a classic; I think I’ve read other Gibson novels, but this was unfamiliar enough that I think it’s a first encounter. Case is our sole POV, but his interactions with Armitage and Molly, and the interestingly textured characters that they run into at each stop, really lend the gritty feel of a complex world that’s ground on with interlocked histories, at national and personal levels.
It gets very ambitious, with a lot of travel to different interesting places, including orbit by the end.