I've only read 2 of the 4 books but this is a unique series. First of all, the world building is top tier. Several alien species with fully realized cultures and biologies. Set in a future where mankind has left behind a dying solar system (the sun has burned out) and humans now live on any number of planets and ships in what was an already established federation of species when they left Earth behind.
Here's what makes these books unique - so far. There is no main bad guy or impending universe destroying cataclysm. The stuff that the characters go through is just "shit happens" kind of stuff. Which I hate saying because it sounds boring but a) it's refreshing to just enjoy a world and the characters and sit in the mud with them and b) I appreciate the low level of drama.
Real life is full of stakes; being late to work for an important meeting, car breaking down and no money to fix it, breaking a leg and there's no elevator or whatever. The difference here is the context. Being an AI in a robot body is not as liberating as the AI expected. A spaceship not working is incredibly dire because no matter how far in the future this is, humans still can't survive the vacuum of space without technology.
Book 1 - A Long Way to a Small Angry Planet, so far is my favorite. After reading it, I could pinpoint what every crew member loves. (Finding that for all my characters is going to be a major factor in my future writing.) And all of them are awesome. Definitely gave me Firefly vibes, in that the crew is so loveable and generally awesome.
Book 2 - A Closed and Common Orbit, follows a whole new set of characters but continues to build on what we know about the other species and the tech that is used in this reality. I don't know if we'll come back around to the crew of the Wayfarer or if all the characters converge at some point.
I'm starting book 3 soon, so yeah, highly recommend.