Last month I've finished the Apple's Silo adaptation of the Hugh Howey's book trilogy bearing the same name. I've had plenty of time to calm down and actually got a second opinion from a person who has (unlike me) not read the books.
TL;DR: Read the book series first (that is, if you're planning on reading the series at all)
Major TV + book series spoilers ahead!!!
As mentioned, I read the books. I read the trilogy a few years ago. Initially though, I abandoned the first book after I had gotten bored by getting through its first half. During my re-read of the first half of the first book, I still had the boredom in my memory but pulled through and finished the book kinda excited. I vividly remember that the second book absolutely demolished any remains of the boredom or uncertainty.
As a slow reader, I was caught off guard! I had finished the second book before I'd been able to get my hands on the third part! Even though I have not written anything about my "readthrough" of the trilogy I recall that finishing the first book, albeit with a bit of perseverance, was well worth it.
What saddened me a little when watching the TV series several years later was how little I remembered of the book trilogy ending... which I personally find a bit weird even after all those years.
A tiny interjection! I actually found out about the series pretty randomly. During one of our company meetings, we shared the screen of an iPad on a TV (or extended the iPad's display, I actually have no idea what it was) and there it was! An advertisement for Apple's own service on the Apple device. Silo. I wasn't excited, I just noted the series in my "Notes to self" in the Singal app and went on with my regular day.
I have to say, I didn't expect much. I am not a fan of modern streaming services and I was actually hoping Apple somehow screwed this up. Despite that tiny inner evil, I saw the potential in the worldbuilding, the possibility to expand the book series itself significantly with interesting characters and side stories from all over the Silo.
After the first episode, I got excited. I simply saw the things I imagined while reading the series. In addition to that, they kicked the series off with the same mysterious beginning as the books! Lastly, there was the nostalgia of my carefree teenage years positively influencing my reception.
After a few episodes, I got scared. The TV series "spoiled" major inflection points of the book series in the first few episodes and this feeling got resurrected in the TV series' conclusion (more on that later). I wasn't sure I liked the faster pacing. I also got insecure about my reading comprehension because I could remember no such thing as the Syndrome. I had to take comfort in a quick search to confirm I was not actually insane, that I haven't missed such an obvious story trait, and that the Syndrome was made up for the purposes of the TV series...
After all that, I enjoyed the slowdown of the series, emphasizing the conspiracy vibes and making sure we develop some deeper understanding of the Silo's funcitoning. I liked the way the hints about the conspiratory nature of the "known" world were given.
I also highly appreciate those tiny bits in the TV series hinting towards future revelations. As an example, I'd like to mention the 18-numbered tiny LED keychain-like thing belonging to the head of IT. I am certain it had to do with the communication that had to be performed with the central/control Silo.
What I think was a major blunder made by the series was the "You're dead anyway, so I might as well reveal something to you..." part. If I recall correctly, in the book series, these reveleations were made later through the character of Solo. I just did not like to see more unnecessary accelerations to the main character's grasp of the conspiracy she was uncovering... Just a personal thing I guess.
The ending was... as expected from the very moment I detected the pacing of the series. Nothing much to say about that apart from one thing that I'm very uncertain about: there was close to zero buildup for the themal/isolation tape plot twist. My memory is very vague on this one but I have a hunch that the book series made at least some attempts to ease the reader into the way the tape's bad quality was discovered. And I might also be hallucinating. Regardless, I think the TV series could do much better job regarding this plot element.
I was excited throughout the series. Mostly due to the nostalgia and anticipation of events according to the books. Not a long ago, I found a person who has watched the TV series but has not read the books.
I've already held the opinion that the TV series uttterly spoiled the plot for any potential reader and that the books would just not get the love they deserve after someone had watched the series and decided to pick them up.
I was a little delighted to find out that my assessment may not be so true! The person's feelings boiled down to the "average"-ness the series has evoked and the lack of detailed world building. I think the books may actually help in this regard. This vastly different experience has made me see the series more critically, but also appreciate the order in which I consumed the two series.
The Silo book series itself started as a collection of short stories. Perhaps this explains my feelings for the first book. My revived memory of the excitement about the series as a whole has made me seriously consider reading the books again. At least before the second TV series starts.
The Silo TV series is a good adaptation. It's got flaws but I cannot shake down the nostalgic feelings I got. For a better standalone format, I would prefer slower, perhaps more mysterious / storybuilding pacing but I loved the visuals and the atmosphere the authors depicted. They absolutely nailed the "recycling" lifestyle of the life in Silo, for instance.
Generally I recommend reading the book series first.