Just played through this at high subtier and had an awful time. Three of the four candidates annoyed me - two for personality and one because he was a blatant ripoff of a published Star Trek character.
Two of the combats were also designed to force PCs to hurt each other. One makes you attack an ally if you fail to deal damage, and gives the creatures three different ways to avoid damage. The other makes you succeed at multiple saves each round to avoid not acting or targeting your allies with attacks. It's a form of difficulty that I do not find fun at all, since you have so little agency over what your character does.
My GM said they hated running it as well - they just wanted it to be over, and all the fake difficulty made it difficult for them to follow tactics and still let the PCs succeed at any task.
This module is designed from start to finish to be a bad experience for players, which is a shame, because the flavor is excellent.
The first encounter is very difficult unless you have one of two skills at a high level, and doesn't provide a map for when things go wrong.
Everything after that takes place in an area where there are multiple impediments to the characters' movement and vision. The enemies, of course, can ignore it all. But having a 3-D combat against very strong monsters for the level where everything the PCs want to do is hampered in multiple ways is not a fun challenge.
There is also an encounter where you lose treasure if you succeed, which is a horrible design choice.
An interesting story was ruined by mechanics that are designed to screw the players over at every turn. My favorite was the hallway that you had to roll randomly to walk down, and getting one of the prestige points relies partially on getting good results on your unmodified checks. Though a creature that can disintegrate a PC before their first turn is obnoxious.