I needed to extend the length of Thunderspire Labyrinth, so used this to make up a set of crypts under the Horned Hold. I ended up making the rooms full 3D, but doing the corridors as 2D.
I've built a ton of WWG fantasy terrain, this set hands-down has the best instructions, and was incredibly well thought out from a construction viewpoint.
It took me about 10 hours to do everything, and that included time spent yelling at Sportscenter and being distracted by anything shiny happening in the room while I built...