This adventure is a strange one, with a couple of major twists built in. It's designed for a one-shot (though it usually takes me about 6 hours to run it) of RP and mystery, not as part of an ongoing campaign.
I've run it three times, with mixed success and many character deaths. It is an extremely difficult module for the pre-gens, with a near-impossibility of total success.
Run well, with the right players, it can be a lot of fun. As the DM, I've always had a blast. The players have had less uniform enjoyment, with about a third of them actively disliking it.
Despite all that, I still recommend it. It's interesting, creative, very open about it's dangers, and inspiring for the rat-bastard-DM in all of us. Very much worth the $5 entry fee.