Slow burn. Political, dramatic and thrilling action sequences. Looks beautiful. Great payoffs. Incredible, intelligent writing.
Half of the main cast has above average acting, and slowly fit into their roles ; the other half do a good job and make the characters their own. Unusually, the rest of the cast, even those that make an appearance for just an episode, are very memorable. So don't be dissuaded by what appears to be a slow story initially.
Kudos to the creators of the show and the original authors of the book. They have gone into meticulous detail for many small things regarding science and culture which most people wouldn't even notice.