I want to like the series, and I have enjoyed some episodes this season more than in season 2. Despite that, I quit. In trying to make sense of my dissatisfaction, I have settled on a few points.
1) Visually, Expanse scenes in space are extremely monotonous. Whether in a ship or showing space, the glaring palette with a small range of colors has really worn me down.
2) The acting. This is the biggest problem. The leads are absolute terrible. On the Roci, everyone except Amos is such an anti-talent that my teeth grind. Miller is good. Fred Johnson is good. That's it. The Prime Minister and his aide (the traitor) are both cartoonish. Avarasarala is passable.
3) Nothing happens which makes sense. Yes, there is action, but nothing seems rational to me. Everything is obviously written into the story to give the characters something to do. This is especially true of the crew of the Roci, who have no business being every important place in the solar system at exactly the right time.
I have read several of the books, so I can tell you that if you're waiting for something to happen which brings events to a logical stopping place, give up now. If you are enjoying the random, nonsensical plot lines, keep going.
As I said at the top, I want to like the series. The production values are great. I like the scale. The solar system has so much concrete interest to it.
Unfortunately, we're not getting a real sense of the solar system, with the long distances, varying flight times, and the sheer impossibility of making some connections.
So, good bye, Expanse.