I played this with Quentin, and actually had a lot of fun.
The character I played is as dumb as a rock and I certainly played that up.
I can see that this is a tough scenario, and you will need to prepare. The gloomspires has its reputation, and without preparation, you will have a problem.
Also, dont be like us, and let the squishy character go first.
That said, I think people looking for a more difficult scenario then normal, will have a lot of fun with this.
I think most people's bad experience comes from a bad or under-prepared GM. This scenario has a lot of things happening in it, with several complex rules. If you dont know those rules, encounters can easily be a pushover, or incredibly deadly, depending on how you interpret them.
I would advise that you play part one, but its not necessary to understand what is going on in this scenario.
There is a lot of lore hidden in it, which you can find if you look for it. There are also several good roleplay opportunities.
All in all, you will miss a lot if you just go murderhobo trough it all. An experienced GM is advised.