Nice effects. My waterfall image is nearly entirely based on the painted shader, from the terrain, water and even the cloud layer of mist.
One of the nicest things in the alpha, I think, is the 'AA bloom' button, it makes the reflection highlights on really shiny surfaces like water and metal look bloody fantastic. Instead of sharp jaggy highlights it makes them dreamy-soft whilst keeping everything else sharp as a knife, more like a camera would react in the real world. Absolutely great.
I've been playing with the hanging valley thing too, I miss entering contests, need to get back into gear and create something for myself instead of for all you buggers!
Public Library - Vol.3, by the way, is going to be based mainly on the new features in the beta.
EDIT: That diamond is lovely!