Purchased this for our DM, so I can only relay what he said, but to him this was a really well-structured module that was easy to prep and fun to run. A lot of high-quality material in this one!
As a player, I found the story really engaging, very creepy (in a good way) and a good mix between plot and combat. It was a lot of fun for our whole party. Two of our players were playing DnD for the first time, so it did take us a little longer than 15 hours, but we all had a blast!