Haven't read the book, and if you're the same I suggest ignoring the reviews bombing it based on that because it's not uncommon for tv/movie adaptations to fail to live up to their book's grandeur or reader's expectations. There's almost always someone saying it's not as good as the book.
So from someone who hasn't read it, I think it's off to a great start. The most notable thing is that this seems like a really well made series, might not be the most mind boggling story off the bar but everything seems to be done right and has no specific weak points for me. This might sound dumb because, of course most shows are done by professionals, but this feels like it was really made by professionals.
I like the story because it feels believable, nothing eccentric yet I'm still drawn to it. I think the best part about the show is the characters and actors playing them; they feel like real people in a real town with real cases, so it's easy to draw you in. Any show can be good, but I think truly great shows are those that manage to get you immersed in them, were you feel like you're in the show, a part of it and their lives. This goes for any genre too, romance, drama and "based on true story" flicks are the obvious ones, but even fantasy or sci-fi and horror. Might not have the craziest story or characters or prismatics visuals, might not even be a 10/10 star show/movie like this one(for me); but when a show fully submerges you that you only think about what you're watching and don't even subconsciously check your phone or anything, that's a good show. Feels like a decent small town murder mystery, sorta reminds me of Mare Of Easttown.
I wouldn't say it's one for everyone, if you're looking for a bullets flying sort of rush search elsewhere, but if you're looking for a good drama to watch this is a pretty good option.