I spent some time this weekend seeing what I could do with the newest RWS tileset, Dark Ruins
Great stuff as usual, though the initial release didn't include a few standard tile types (eg room with two doors opposite and two variations of hall end with one door). The other thing with this tileset is that you have to be careful with cave pits and bridges. Bridge end pieces need another tile next to them. The "lookout areas" into pits don't always mesh well with adjacent tiles, leading to spots with wall on one side/clear from the other syndrome if you're not careful. This restricts the layout you can make pit areas.
The final oddity in the tileset was a metatile that does not connect to any other walkable areas, though it does have doors in it, so you could access the area by using a door elsewhere.
The other thing is RWS has put in a circular door for this tileset, but the texture is the Aztec calendar stone. I'd like to see a little more generic alternative, the door makes the tileset strongly meso-american (or maztican for Faerun).
But since it was just released, can't really fault RWS, especially since the tileset is so good looking. The tileset also happened to be a good fit for an area I wanted to work on, a dungeon built by ogre mages. The tileset has a strong "not built by humans" look imo.
New tilesets from RWS are always great, the quality I see from them is always excellent.