Watched the last episode last night (thank you Amazon for releasing things at midnight GMT...). Overall I think that they handled things well with the constraints that they apparently had in terms of budget/episode count. If they'd been able to make it a 12-episode season a lot of things would have made a bit more sense and have been clearer, but they managed to wrap everything up quite well under the circumstances and hit all of the major plot points. If they do make more using the final books (movies/miniseries/etc.) they set things up well for it.
A few thoughts (warning: book spoilers ahead):
I wasn't the biggest fan of their adding in the extra drama and making it look like they were going to kill of Peaches and Bobbi. I'd seen a lot of speculation that they were going to pull their deaths far earlier into the story for dramatic effect, and they certainly made it look that way for a while there. I was rather surprised to see that the prognosis for Peaches' condition being that she had an expected lifespan of 5 years given how much longer the time jump to Perspolis Rising is than that (~30 years or so) and she is still around then.
I didn't really understand the reason for having changed the circumstances of the assault on the station- I guess explaining that they had set things up so that the landing pods (which had more than one person in them, like the ones used to assault the science station early in the series) were tumbling and looked out of control so would be less of a priorty for the railguns targeting systems would have taken too long? I didn't understand why they kept the plan such a secret as well, other than to be a surprise to the audience- which they have to figure a decent number of already knew about from the books. I guess having the Roci in harm's way from the railguns vs. hanging out on the other side of the gate until the guns were down also added to the drama and excitement, but I thought the original worked well- it just didn't make sense for them to be there IMO.
A consistent problem that I've had with the series vs. the books is how a number of things that in the books are very well-thought-out and smart plans are reduced to a heat-of-the-moment decision on the screen. Bobbi's PDC/railgun trick to knock out the Pella a few episodes ago is a good example, and setting things up so that Marco and his ships would go Dutchman going through the gate was another classic example. In the book Naomi had everything pretty much figured out from the data and knew exactly what needed to be done to set it up so they wouldn't make it through vs. it feeling much more like a complete shot in the dark in the series.
One thing that I did think that the series did better was with Naomi and the decision to (as far as she knew) kill Filip along with Marco and his fleet. Her having to push the button to set things off and her reactions after that hit a LOT harder to me than the book did. The change with how Filip got off the Pella as well wasn't bad- and it did set him up a bit better for the future than the book did since in the book he literally had nothing when he went AWOL vs. having the repair skiff in the series.
It was interesting how they handled Xan's movement after being brought back... it seemed somewhat excessively robotic compared to how I remember the final two books describing it, but after reading Strange Dogs it does seem like that was pretty accurate. I kind of wonder how much of that was the actor and how much was done in post...
I'm kind of ambivalent to the change with regards to how Drummer(/Michio) came to be the head of the Transport Union. On one hand, the book set things up so that Avasalara had orchestrated it so that Holden would be the one who objected to being the President and recommended Michio(/Drummer)- but Avasalara wanted a Belter to be the one to head it up because she knew it would never succeed otherwise. Whereas the series made it seem like Avasalara didn't actually want a Belter to be running it and that it had purely been Holden's (and Drummer's) idea (though she accepted it in the end).
Finally- I've got to give them props for the final scene of the Roci essentially 'flying off into the sunset.' It was a great closure for the show, and also did a great job of highlighting the theme of just how insignificant all of the events were in the grand scheme of the universe. I sincerely hope that they are able to work out making the rest of the books into either a miniseries or movies... from what I understand, the production company not wanting to do it any more is why they aren't planning to at the moment, but if another steps up I'd love to see Persepolis Rising, Tiamat's Wrath, and Leviathan's Fall on-screen.
I also really hope that they release a 10-volume set of all of the books (including the upcoming Memory's Legion with all of the novellas) down the line- I don't really buy physical books much any more, but these I'd love to have around in hard-copy form.