Everybody who likes sci-fi should watch The Expanse. There's a reason it's critically acclaimed.
Okay, so in terms of the differences, I will try to explain the main ones in a way that doesn't spoil The Expanse (but given that the topic is for people who like BSG and are wondering whether to watch The Expanse and what's different about it, I am going to spoil BSG).
Firstly, the technology of BSG is a lot more advanced than that of The Expanse. BSG has FTL drives, anti-gravity, enormous carrier spacecraft, and so on. Technology in The Expanse advances over the course of the series but doesn't start off anywhere near what the Twelve Colonies and the Cylons have at the start of BSG.
Secondly, BSG almost immediately smashes humanity down to the scale of a small fleet, and for the most part keeps them as a relatively unified tiny society and follows the leadership of that society during the course of the show. You can just about understand the entirety of human society in BSG, as long as you don't ask awkward questions like where all the news reporters are coming from. The Expanse has a much bigger and more complex vision of human society, with three major factions that each have their own internal divisions (Earth, Mars, and the OPA - a loose confederation of the inhabitants of the asteroid belt and moons of the outer planets). Though the series does follow some of the leaders of those factions, it is more concerned with the interactions between them. That includes military interactions but also much more general day-to-day stuff. The military in BSG is much more in focus, since it's the structure that the new society builds itself around.
Thirdly, because BSG makes humanity so small, it can ask some philosophical questions about the scalability and survivability of societies in general. Questions like what the role of the military is when there's nothing like a police force, what kind of missions can be considered acceptable when society is on the brink, whether an incompetent leader can be tolerated in the name of democracy, the kind of restrictions that should or shouldn't exist to ensure society survives, the extent to which it's okay to make up a dream to give that society a purpose, and so on. The Expanse doesn't position itself to do this. It's much more geopolitical than philosophical. Geopolitical is the wrong word of course, maybe should be heliopolitical.
Fourthly, BSG brings in a lot more spiritual and religious elements than The Expanse ever does. Right from the start there's the contrast between the polytheist humans and the monotheist Cylons, and this continues throughout the series, with prophecies, visions, head Six and head Baltar who turn out to be angels, and the whole deal with Starbuck in seasons 3 and 4. The Expanse doesn't have that. There are some elements of the show that the humans of The Expanse can't explain, but there is no suggestion that they're supernatural. The forces acting in the world of The Expanse are political and technological.
Fifthly, despite the opening, BSG doesn't have a plan. The series takes big directional shifts in later seasons and by season 3 they are clearly making it up as they go along. The Expanse is following a pre-defined structure. As a result, it doesn't (and hopefully won't) find itself scrambling around trying to tie up loose ends that it created in earlier seasons, like BSG does.
Lastly, BSG ended in a way that narratively wrapped up the stories. People can argue forever about how well it did that, but it did it. The Expanse as a TV show won't be completing the story of the novels, since the sixth season will be the final one. Because of how the books are written, that's actually a reasonably good place to end the TV show, and I'm sure they will make an effort to give it the most satisfying end possible, but I think it's highly unlikely to be able to wrap up everything. People who don't like plot lines being left open should keep that in mind.
The first season of the Expanse is, in my opinion, pretty bad. Great world and quite well produced but the storytelling is so so awful, it's boring and demotivating most of the time. No sense of stakes.I love BSG it is one of my favorite series of all time. And I keep reading that every BSG fan should give the Expanse a watch. I remember catching the first episode a while ago and not really liking it that much. Should I watch it, what do you think?
I love BSG it is one of my favorite series of all time. And I keep reading that every BSG fan should give the Expanse a watch. I remember catching the first episode a while ago and not really liking it that much. Should I watch it, what do you think?
Give it a try. If you don't like it a few episodes in, then don't waste your time.
The Expanse reminds me of Mass Effect a lot if that makes any sense to you.