Unity Doesn't have a built in PBR solution yet....It does have something in Unity 5...but that isn't available quite yet. Unreal 4 is the new hotness. As far as I know...DDO isn't quite setup for PBR-ish textures quite yet? I think thats coming with the new version.
I'd also recommend Uneral 4. With the new changes, and how well preview works in the editor, I'm finding I can test and iterate a lot faster then I could in UDK3 or Unity. and PBR really allows you to push your materials further with less time invested. (real time reflections are wonderful!)
I'm making a scene using newly learned programs NDO and DDO. I havn't really spent much time with the scene in UDK other then for the block out and quick refresher on materials etc. I know the previewer Quixel uses is PBR and I believe that is how Unity is set up? I'm not huge into the technical side of these things, but…