I'm a MasterMaze enthusiast. They are expensive but the quality of the sculpting and painting and the attention to detail are excellent -- your lovingly painted minis will no longer feel embarassed standing around on a vinyl mat or a whiteboard. I find the pieces quite durable, having dropped them from table-height without so much as scratching them. They are easy to set up once you've had some practice. I never bother with the bow-tie connectors that you can use to join the tiles.
I have never set up an entire dungeon with them, except as a showpiece for photographing minis. I use them for battles, building only as much of the dungeon as I need at the moment, with the option of building outward to follow the action as the battle unfolds.
Start with one or two of the basic rooms and passages sets. Be forewarned that you can't make absolutely everything with them -- the options for circular rooms are limited, for example, but can be approximated using diagonal wall pieces. For large rooms and caverns you're going to need many, many sets. Also, it's hard to stand minis on some of the stair pieces; I'd like to see them remade with wider treads.
Overall, I'm crazy about them and always look forward to the next set.