There's been a new edition made since my original posting, so this is about the old edition.
I enjoyed the game, but that was because I enjoyed the company of the people I played with.
Setting up each dungeon took a while, but once we started, gameplay moved right along. My main complaint is that things got a bit repititious as there's not much different your characters can do. A fine beer and pretzels game, and I'm glad we did the campaign, but I don't plan on playing anymore.
Edit: the non-campaign game may be fine, if you can change characters between dungeons so it has less of a feel of just doing the same thing over and over.