Good starting adventure for new DMs and players. Overall my group and I really enjoyed our time in this dungeon. The story of the dungeon is compelling and teased out at a good pace across the adventure.
Here are a few minor criticisms:
1) Not a lot of social interaction/role play opportunities. There are abundant social interaction chances in Purdey's Rest (the main town), but my PCs were only there twice (once at the beginning and once, unnecessarily, halfway through because they got stuck on a puzzle and thought they had to go back to get the answer). As well, one ecounter can be resolved via social interaction in the dungeon itself, but otherwise it feels very hack and slash. I like that kind of game most of the time, but some of my players definitely felt a little constrained. Would have been nice to have certain parts of the dungeon that prompted you to go back to Purdey's Rest to get some knowledge in order to progress (and thus have some chances at RP).
2) Very linear. If you're looking for a sandbox adventure this ain't it. This is less a criticism and more of a note to future buyers. This dungeon is very much put together to shepherd a group from the beginning to the end. That feels like a conscious decision on the author's part, and likely for good reason considering this is aimed at beginning DMs and players. New DMs and players need more of a laser focus and this advenutre provides it.
3) Would have liked some scaling options. This adventure is designed for 4 PCs, and doesn't provide any guides for deviating from that. It would have been nice to have been given some direction on how to change this for various party sizes. I ran this for my group of 3 PCs and used the following guideline: if it was 4 or more monsters, then drop a monster, otherwise drop the HP by 1/4 for each monster. This felt right in some instances, but too easy or hard at other times.
4) Resting can be a bit too easy. There are no mechanics for any random encounters, and the dungeon specifically provides a location where long rests are always safe, so my PCs never felt particularly run down as they could always long rest after every encounter (not that they always remembered to do so). There was no in game way to say "You can't because..." without changing the rules on them.