Okay, I have lots of thoughts about this book. The first is that the dialogue/conversations were very Checkovian in nature. Meaning that it was full of subtext and more than a few sentences in the dialogue were cut off or trailed off seeming to imply something without expressly stating anything. I found this frustrating and allowed the reader too many suppositions to support the themes of the book appropriately. In fact, there were so many times I read a conversation and realized I didn't care about ANYTHING that was discussed.
Next, the characters (especially the protagonist) were portrayed as child-like so often that it became unbelievable at certain points that these were adults capable of making coherent decisions and more than once I thought perhaps Eleanor was on the autism spectrum because of the way she focused on things and rationalized events as they happened. Which leads into my next criticism, the fact that all of the characters seemed to 'take inventory' of things in the house so often that I could probably make a list of all the things in each room, but I couldn't tell you the significance of any of them or the point in all of these multiple scenes of characters taking inventory.
There was some beautiful, lyrical prose and moments of real suspense that I found inventive and realistic, which is why this book got 3 stars but as a whole I don't think it stands up in modern times. I will speak about the changes made in the TV series adaptation on Netflix in my video as I generally think this was one instance where the TV version actually corrected things I didn't like about the book and strengthened the story.
All in all, it took me entirely too long to finish this book because I didn't enjoy it as much as I was hoping to, but there were really great elements and its clear why this is a classic in the horror genre.