In the last two days I had a play with dDo and nDo2. I must say I am very happy with what it can do! Its a very automatic process however, and many users suggest to use this as a base or just to learn how materials work.
I modelled a wall rock two weeks ago and I decided to experiment with dDo, I am very happy with the results. It automaticly places details depending on both the OS Normals, Normals and Occlusion and what kind of material is it, hence why dDo recommends highly to make a colour map, to mask the areas of different materials by using colour. By just using the OS Normals, Normals, and Occlusion it spit 4 maps automatic with the press of a button.

Here is where dDo can be checked out:
http://quixel.se/ddo/

This video, even do its very long, its worth checking out, because it explains very carefully how dDo is used:
http://www.youtube.com/watch?feature=player_embedded&v=hncqbwkGbM4

And last, a little screenshot using Marmoset Toolbag, another delight to check out!

And the Maps that it spit out! With a wireframe.