So I finally actually got to give this a try. It's a night and day difference from the built-in-shadows. These look fantastic! I am having some problems with shadow acne however. On surfaces facing the light everything's fine, but on surfaces closer to parallel to the light I get a lot of artifacts. At low bias values (which is what I'd prefer to use, as higher ones cause peter panning and leaks) these are pretty serious. Even at very high values it doesn't disappear entirely on some surfaces. (The first screenshot is at bias 0.05, the second is at bias 1.0.) Any tips for dealing with this? I don't know much about shadows. I tried fiddling with Normal Bias, which sounds like it could help, but it didn't seem to do anything. There also seems to be a bug with spot light shadows if you stand right on the edge of the light.