I started watching this when it came out last year, but quickly abandoned it after one and a half episodes. Not because I didn't like the premise or genre1, but there was just something about the protagonists of this first episode that didn't convince me to keep going back then. However, I was sure I would need to revisit it at some later point in time. When I finally did, I was intrigued from the start and realized that I hadn't even gotten to the main timeline before. What I initially thought to be the main protagonists were just minor characters making up what would be part of the backstory of the series.
The actual protagonist, Rebecca Ferguson, is fantastic and carries this show which gives off Snowpiercer and maybe even The 100 vibes, but without most of the action and brutality. I'd probably pick Silo to be the best among those three. I'm enjoying every second of it and don't think that the pacing is slow at all, but I would understand if not everybody felt the same way.
1 mysteries in dystopian settings are among my favorites