I binge-watched in one blank night season 4 of The Expanse as soon as it was released on December 13 - I really looked forward to it, being it my very favorite current and/or recent science fiction series; one as good as the greatest ones like Battlestar Galactica.
Some minor spoilers ahead.
The first half of Season 4 is slow. It isn't as compelling as seasons 1, 2, and 3. After these somewhat disappointing episodes that seemed a bit less polished and losing pace, I was afraid for the series, given the change in production company (Amazon picked it up and saved it from cancellation; thank you, Jeff Bezos; it appears like he was personally involved in this decision). Fortunately the second half of the season went back to its suspenseful, fast-paced thrills, and got to be almost as good as the first three seasons. I rate seasons 1, 2, and 3 a full and perfect 10 out of 10, and season 4, 8.5 out of 10. The lost points are due to the slow pace of the first five episodes; I would say that episodes 6 through 10 once again became almost a 10 out of 10 (9.5?), so there is good hope for the next season.
This is as far as I went in the books. We are at the same point now, for me. I read the first four books, to the end of Cibola Burn, which corresponds to season 4. I do have books five and six already saved to my iPhone's Kindle app. I'm not sure if I'll read them and spoil the fun for the next season, but I probably will because I can't wait for the continuation (next book, Nemesis Games) as it will be several months until Amazon hopefully releases season 5.
Why is The Expanse so good? First, because this is a spectacular story; one of the best space operas ever written. The quality is up there at the same level of the Hugo and Nebula-winning masterpieces of the past. I highly recommend the books. The plot is more original than most. Sure, we've seen the idea of portals left behind by an advanced alien species. But the creepy protomolecule and the extremely advanced focus on politics with the three factions, Earth, Mars, and the Belt, make for some very original storytelling and very compelling and well-developed characters, for a sci-fi work. Not only the main plot is interesting, but there are also several sub-plots that work well.
Second, the series delivers one of the best book adaptations I've ever seen in cinema or TV. This is a series that doesn't anger the fans of the books. The special effects are some of the best in the business, making the whole look very realistic. One does have the impression that one is watching a documentary about humankind's distant future, with believable space stations, colonized asteroids and moons, planets, spaceships, and matching technology. Nothing is over-the-top, even the space battles. The acting is more than appropriate; maybe, unfortunately, with the exception of the very main character, Holden, whose role is played by an actor who is a bit less talented than his colleagues who are in the other roles - but he is still adequate and doesn't sink the ship. The dialogue is well-written, including in the fact that it goes all the way to the effort of having a Belter dialect that makes sense.
Part of the fact that season 4 is to be rated lower than seasons 1, 2, and 3, is somewhat the fault of the source material: once the protomolecule mystery gets partially solved by the end of book 3, there are still very interesting directions the authors (yes, in the plural - the listed-as-one author of the book series is actually a pseudonym behind which there are two authors) are driving the story into, but taking away one of the most striking elements of The Expanse makes it a bit less phenomenal. There is plenty left, though. We still want to learn more about the Builders and about the other civilization that wiped them out. Another element that makes of Book 4/Season 4 something a tiny bit less interesting is that one of the main characters, Bobbie, is down to a kind of domestic life in Mars, and has her kicking-ass wings a bit clipped. She looks gorgeous with her hair down, though, and by the end of Season 4, we learn that she is getting back into the future action, so, again, it bodes well for season 5, given that Bobbie is one of the best parts of The Expanse.
Anyway, it's a pleasure to watch something so well done (visually, acting-wise, and dialogue-wise), depicting accurately something that is very well-written to start with. It's a win-win: great rendition of a great source material.
To every and all science fiction lovers, if you haven't seen The Expanse yet, get it immediately; you won't regret it.