We played this scenario with a mixed group of adults and juniors. Our party was all level 4 and quite combat focused. The overall scenario story is o.k. and expands the story arc of the the mini triology. It allows serveral type of charcters to have their moments to shine, but I feel that following this ideas mislead the author to a point where certain classes are almost manatory. Playing this senario without any characters skilled in survival or performance or without at least one cleric or paladin is quite difficult. The enemys are all well prepared and their combat tactics unforgiving of player mistakes which results in quite deadly and crippling encounters.
Spoilers from here on...
The advenutre penalizes the party heavily with attribute damage caused by undead and haunts, ending in a point where the monk had -10 Strength, the Rogues - 2 Strength and 2 negative levels and the fighter got possessed. By the mercy of the game master all wisdom damage went to a npc thus killing him that way. I feel this is way over the top for what a lower level group should expect to be confronted with. The mazes that are scattered throughout the dungeon cause lot of fatigue and exhaustion among the characters weakening them further. Together this results in a lot of long term debuffs that weakens the group to a point where they are no longer able to handle the anyway challenging fights.
I cannot recommend this scenario to inexperienced players and a party without a bard and atleast a cleric or paladin.