I voted for RE's as well since it is a very nice map indeed, is a difficult style to get right and think this one did and also it fit the bill very well. Not only that but its the sort of map you can just fling down when you need somewhere ad hoc for your party to investigate and its interesting. RE you were always able to do the main challenge whenever you felt like it but if you win you will have the max 3 compasses which means that you would have to go to that club.

My second vote went to gaemon because it was also a place that was obviously below ground and was not a bad map but without any kind of top down we have no idea what shape rooms they make so it would be less useful to play ad hoc. Still, well done.