I promised some people here to write a review a while back so here we go:
Dwarven forge makes 3D ,terrain, dungeons and cities to use in roleplaying games, for minature games or in boardgames like Heroquest and Descent. They are modular and of a rather standard size so you can mix them with a variety of other products for 25mm miniatures but they work for 15-30mm.
This is part of a dungeon I ran with some friends a few weeks back (sorry about the miniatures, I had mine packed somewhere due to me moving next week). You can see the basic floor and walls. Notice that the doors can be opened and the hidden door thats is slightly opened in the left room. There is also a bench in the small middle room.
The whole thing do add a new level both to RPGs and simple boardgames and is really sweet to have. This is manly from the standard dungeon.
Appearance: They look rather awesome, the ones I got are all pre-painted but you can also buy them unpainted for a lower price. I would still go for the painted though since they look really good. There are plenty of details, particularly on doors and treasure items.
Score 4/5 (but the cavern set and treasure sets are easily a 5/5)
Durability: Most of the sets are made in something they call Dwarvenite. It is very durable and can take a good beating with a hammer even. A few things like treasure items and the old master maze system were made in resin and are weaker but it wont generally break or even loose color. There is nothing else I ever seen that can take this type of punishment without breaking.
Flexibility: You can build most dungeons and caverns as long as you have enough sets. The base sets will only allow you to build 90 degree corners on your dungeons so while you can get tiles for almost every possible variant it will get expensive and that drags down my score.
Price: A single base set is $70 painted and $50 unpainted (you can buy 3 or 4 sets in a pack a bit cheaper). I am using about 3 sets in the picture together with a large floor tile (in the right room) and a few pieces from the accessory pack. There is also 1 corridor piece. A painted triple set is $195, unpainted $135 but I recommend 4 sets. There is an insane amount of accessory packs so things can become expensive fast. You do get a lot for the money but unless you go in on one of their kickstarter project it wont be cheap. And that is just the dungeon stuff, if you want caverns and to build a small town as well it will be expensive indeed.
Final score: These things are more or less a must if you play any kind of dungeon crawls. Cardboard just ain't the same thing and it makes combat so much easier.
Not a great picture (I blame my phone), but it is a small treasure room with a bed, a statue and a pile of silver coins.