The Promised Neverland starts out super strong and hooks you right in. As many have echoed, the first arc is the best as it's is well thought out and the execution of the tension was great. Even up to Goldy Pond was interesting, but then it goes down hill from there. The characters become flat and have no more character development. The overall plot starts to get mess as more and more characters and plot twists are introduced. By the end, you're just glad there's an ending that wraps up the hot mess of the final arcs. Too much got added in, and it clearly shows. I still think it's a good manga to burn a few hours of my day, and the art is incredible the entire time. However, it really could have been better if the mangaka had not tried to add so many characters so much world building.
Overall, great art, still a decent read, but it's not as good as it started.