First off, I don't understand why so many people love this book. I think after reading Holly Jackson's popular books, my standards have increased tremendously.
The book at first wasn't too boring, they uncover tiny details and there's a lot of speculation. But as I kept reading I got increasingly bored. There wasn't much actually happening and the book also focused a lot on high school drama such as couple fights and rumours and mean girls and they did play a part in the story but it felt drawn out.
In the end when they found out the cause and reason for the death, i was slightly surprised, but it wasn't anything groundbreaking. The explanation basically came out all at once from one character and it didn't feel like a plot twist. It was fun to guess who did what and see how it played out but I didn't feel satisfied in the end.
As for couples and romance, the book had a few couples but I really didn't love many of them. Usually I'm all for book couples, but here the ones that were positive didn't make me feel satisfied, as the buildup was sudden and insufficient to make me want to ship the two characters together. There was quite a bit of unnecessary kissing which I usually don't mind, but in this case it felt more like a sexual relationship rather than one that felt whole with people that were actually meant for each other.
Overall, I don't hate the book enough to not want to finish reading the series, but I wouldn't recommend it to anyone.